What causes allergic skin rashes. How to identify different types of skin reactions. Which antihistamines are most effective for treating itchy skin conditions. When to seek medical attention for persistent skin issues.

Understanding Allergic Skin Reactions: Causes and Symptoms

Allergic skin reactions occur when the body’s immune system overreacts to certain substances, known as allergens. These reactions can manifest in various forms, with the most common being contact dermatitis, hives (urticaria), and eczema (atopic dermatitis). But what exactly triggers these uncomfortable skin conditions?

Common allergens that can cause skin reactions include:

• Plant substances (e.g., poison ivy)
• Metals (especially nickel in jewelry)
• Soaps and detergents
• Fragrances and cosmetics
• Pet dander
• Certain foods (e.g., nuts, fish, eggs)
• Medications (e.g., antibiotics, aspirin)

Interestingly, it’s possible to develop an allergy to substances you’ve previously tolerated without issue. This phenomenon underscores the dynamic nature of our immune system and the importance of staying vigilant about potential allergens.

Distinguishing Allergic from Non-Allergic Skin Rashes

How can you tell if your skin rash is allergic or non-allergic in nature? The key difference lies in the cause and the body’s response. Allergic rashes result from the immune system’s overreaction to allergens, while non-allergic rashes are caused by irritants that would affect anyone’s skin upon contact.

Non-allergic rashes often appear quickly after exposure to irritants like harsh chemicals or strong detergents. They typically cause pain rather than itching and are confined to the area of contact. In contrast, allergic rashes may take longer to develop, are usually itchy, and can spread beyond the initial point of contact.

Types of Allergic Skin Rashes: Hives and Eczema

Among allergic skin reactions, hives and eczema stand out as the most prevalent. But how do these conditions differ, and what are their distinct characteristics?

Hives (Urticaria): The Sudden Invader

Hives appear as red, raised bumps on the skin, often accompanied by intense itching, burning, or stinging sensations. They can develop rapidly in response to various triggers, including:

• Insect stings
• Pollen (particularly during spring and fall allergy seasons)
• Certain medications
• Specific foods

One of the defining features of hives is their transient nature. Individual welts may disappear within hours, only to be replaced by new ones in different locations. This pattern can persist for days or even weeks in some cases.

Eczema (Atopic Dermatitis): The Chronic Condition

Eczema represents a more long-term sensitivity to environmental allergens. It typically manifests as patches of dry, red, and intensely itchy skin. Common areas affected include:

• Around the eyes
• Hands and feet
• Inside of elbows
• Back of knees

Unlike hives, eczema tends to be a chronic condition with periodic flare-ups. These episodes can be triggered by various factors, including seasonal allergies, stress, and changes in climate.

Preventing Allergic Skin Reactions: Proactive Measures

Prevention is often the best strategy when it comes to allergic skin reactions. But what steps can you take to minimize your risk of developing these uncomfortable conditions?

1. Identify and avoid known allergens
2. Wear protective clothing or gloves when exposure is unavoidable
3. Wash skin promptly with mild, fragrance-free soap after potential exposure
4. Use cool, wet compresses to soothe affected areas
5. Apply fragrance-free moisturizers to maintain skin barrier function

It’s crucial to resist the urge to scratch affected areas, as this can lead to skin damage and potential infections. Instead, focus on soothing the skin and managing symptoms through appropriate treatments.

The Role of Antihistamines in Treating Allergic Skin Rashes

Antihistamines play a crucial role in managing allergic skin reactions by counteracting the effects of histamine, a chemical released by the body during an allergic response. But how exactly do these medications work, and which ones are most effective for itchy skin conditions?

How Antihistamines Work

During an allergic reaction, the immune system releases histamines, which cause the characteristic symptoms of allergies, including itching, inflammation, and swelling. Antihistamines work by blocking the effects of these histamines, thereby reducing the intensity of allergic symptoms.

While antihistamines can’t speed up the healing process of a skin rash, they can significantly alleviate the discomfort associated with itching, allowing the body’s natural healing mechanisms to work more effectively.

Types of Antihistamines for Skin Allergies

Antihistamines are broadly categorized into two groups: first-generation and second-generation. Each type has its own set of characteristics and potential benefits for treating allergic skin conditions.

• First-generation antihistamines (e.g., diphenhydramine, chlorpheniramine)
  • Faster-acting and potentially more sedating
  • Useful for nighttime relief of itching
  • May cause drowsiness and impair cognitive function
• Second-generation antihistamines (e.g., cetirizine, loratadine, fexofenadine)
  • Less sedating and longer-lasting
  • Suitable for daytime use
  • May be more effective for chronic conditions like eczema

The choice between these types often depends on the specific symptoms, the time of day, and individual response to the medication.

Choosing the Right Antihistamine for Itchy Skin

When selecting an antihistamine for allergic skin reactions, several factors come into play. How do you determine which antihistamine is best suited for your particular situation?

Factors to Consider

• Severity of symptoms
• Duration of relief needed
• Potential side effects
• Time of day when symptoms are most bothersome
• Presence of other medical conditions

For acute, severe itching, a first-generation antihistamine like diphenhydramine might provide faster relief, especially if taken before bedtime. However, for daytime use or long-term management of chronic conditions, a second-generation antihistamine may be more appropriate due to its non-sedating properties and extended duration of action.

Recommended Antihistamines for Different Scenarios

While individual responses to antihistamines can vary, here are some general recommendations based on common scenarios:

• For acute hives or sudden allergic reactions: Diphenhydramine (Benadryl) or chlorpheniramine
• For chronic urticaria or daily management of eczema: Cetirizine (Zyrtec), loratadine (Claritin), or fexofenadine (Allegra)
• For nighttime relief of itching: Diphenhydramine or chlorpheniramine
• For daytime use without drowsiness: Cetirizine, loratadine, or fexofenadine

It’s important to note that while these recommendations can serve as a general guide, consulting with a healthcare professional is always advisable for personalized advice, especially for long-term use or in cases of severe allergic reactions.

Complementary Treatments for Allergic Skin Rashes

While antihistamines are effective in managing the symptoms of allergic skin reactions, they are often most beneficial when used in conjunction with other treatments. What additional measures can be taken to soothe itchy, inflamed skin and promote healing?

Topical Treatments

• Hydrocortisone cream: A mild steroid that can reduce inflammation and itching
• Calamine lotion: Provides a cooling effect and can help dry out oozing or weepy rashes
• Moisturizers: Help maintain skin hydration and restore the skin barrier
• Oatmeal baths: Can soothe itchy, irritated skin

Lifestyle Modifications

In addition to topical treatments, certain lifestyle changes can help manage allergic skin reactions:

• Wear loose, breathable clothing to minimize skin irritation
• Keep nails short to prevent skin damage from scratching
• Use hypoallergenic laundry detergents and avoid fabric softeners
• Maintain a cool, humid environment to prevent skin dryness

By combining these complementary treatments with appropriate antihistamine use, many individuals find significant relief from the discomfort of allergic skin reactions.

When to Seek Medical Attention for Skin Allergies

While many allergic skin reactions can be managed at home with over-the-counter treatments, certain situations warrant professional medical attention. But how can you determine when it’s time to consult a healthcare provider?

Signs That Indicate a Need for Medical Evaluation

• Persistent or worsening symptoms despite home treatment
• Signs of infection (increased redness, warmth, swelling, or pus)
• Rash covering a large portion of the body
• Accompanied by fever or other systemic symptoms
• Severe discomfort that interferes with daily activities or sleep
• Uncertainty about the cause of the rash

In these cases, a healthcare provider can offer a more comprehensive evaluation, potentially including allergy testing to identify specific triggers. They may also prescribe stronger medications, such as oral corticosteroids or immunomodulators, for severe or persistent cases.

Emergency Situations

Some allergic reactions can be life-threatening and require immediate medical attention. Seek emergency care if you experience:

• Difficulty breathing or swallowing
• Swelling of the face, lips, tongue, or throat
• Dizziness or fainting
• Rapid pulse or palpitations

These symptoms may indicate anaphylaxis, a severe allergic reaction that can be potentially fatal if not treated promptly.

By understanding the nature of allergic skin reactions, knowing how to choose the right antihistamine, and recognizing when to seek medical help, individuals can effectively manage their symptoms and improve their quality of life. Remember, while antihistamines and home remedies can provide significant relief, persistent or severe allergic skin conditions should always be evaluated by a healthcare professional to ensure appropriate treatment and prevent complications.

Best Antihistamine for Allergic Skin Rash – Curist

By Elena Dang, The University of Texas at Austin College of Pharmacy

Curist delivers FDA-approved allergy medicines to your door at half the price of traditional brands. We hope everyone stays safe and healthy during this time.

If you were recently outdoors and returned home noticing a red, itchy patch on your skin, you may have an allergic skin rash. Have you ever wondered what an allergic skin rash is, what causes it, and what antihistamines can best treat an allergic skin rash? Continue reading to learn more!

An allergic skin rash is also known as contact dermatitis, which simply means skin inflammation from touching something that makes your body’s immune system overreact. An allergic skin rash may appear when your body comes into contact with an irritant or an allergen causing a patch of your skin to be itchy, red, and inflamed. It can appear within minutes, hours, or several days of coming into contact with the irritant or allergen.

An allergic skin rash is caused by allergens which cause the immune system in some people to overreact. Some common allergens include plants like poison ivy, jewelry made of nickel, soaps, fragrances, or cosmetics. It is even possible to develop an allergy over time to things you have used before! 

On the other hand, non-allergic skin rashes are caused by irritants, which are substances that would cause an immune system response with anyone who comes into contact with it. Common irritants like permanent hair dyes, harsh detergents, or chemicals can cause a non-allergic skin rash which typically results in a painful skin rash that appears quickly after contact. 

In both cases, the skin symptoms are most severe where you touch the allergen or irritant. If you want to know what substances may be causing your skin rash, you can see an allergist for a skin patch test, where they will help you identify the problematic substances. It will help your doctor if you write notes with details surrounding the skin rash such as where it touched your skin, how much of the substance you encountered before the reaction, and any activities 1-2 days before the skin rash appeared.  

The two most common types of allergic skin rashes are hives (urticaria) and eczema:

• Hives (Urticaria) appear on the skin as red, raised bumps that are usually itchy, burning or stinging. Hives can result from an insect sting, pollen (like appear in spring allergy season or fall allergy season), pet dander (like that from dogs or cats), medications such as those for high blood pressure, antibiotics, or aspirin as well as certain fresh foods like nuts, fish or eggs.
• Eczema (Atopic Dermatitis) is a more long-term sensitivity to environmental allergens that generally appears around the eyes, feet, hands, inside of elbows, and back of knees as cracked, inflamed, red, itchy, dry skin patches. Eczema can flare up from time to time and can happen with seasonal allergies.     

The best thing you can do to prevent an allergic rash is to avoid contact with the allergen or irritant that causes the skin irritation. So if you think you will be exposed to something that will cause an allergic skin rash, wear protective clothing or gloves. If you do come into contact with the allergen or irritant, wash your skin immediately with warm water and mild, fragrance and dye-free soap. Pat the area dry and use a cool, wet compress to calm the area.  

It is also best to avoid scratching the irritated, red skin as it can lead to a possible open wound that can get dirty and infected. You can use fragrance-free moisturizers or anti-itch creams like hydrocortisone or calamine to soothe your skin.

During an allergic reaction, your body’s immune system releases natural chemicals called histamines that cause itchy red, inflamed skin. Although it will take time for your body to naturally heal, antihistamines can help relieve the itching associated with skin rashes like hives and eczema. Try your best to avoid scratching the allergic skin rash, because if you open a wound, it can lead to an infection and even longer healing process. Use antihistamines, fragrance-free moisturizers, or anti-itch creams like hydrocortisone or calamine to relieve the itchiness and soothe the irritated skin.  

Typically an allergic skin rash will appear within minutes or hours after your contact with an irritant and the itching symptoms will go away within two to four weeks. An allergic skin rash is limited to the area of skin in contact with the trigger. Use of antihistamines may not reduce the amount of time it takes for the skin rash to go away, but antihistamines will help reduce the itching while you have the rash. If the allergic skin rash does not resolve within a couple weeks or if it worsens over time, you should contact your healthcare provider for evaluation. 

The best antihistamine to take during the day to help with allergic skin rashes is Curist Allergy Relief (levocetirizine) or another antihistamine like fexofenadine or loratadine, which can provide 24-hour symptom relief without making you feel sleepy. For better symptom relief at night, you may use a first-generation antihistamine like benadryl, which can reduce your itchiness and help you sleep. These antihistamines can help you relieve the discomfort and itchiness of the allergic skin rash while your body heals the skin.    

The good news is that an oral antihistamine tablet like levocetirizine (brand Curist) can help relieve the itchiness and discomfort from a rash; however, you will need to let your body heal the rash with time. In addition to an oral antihistamine, an anti-itch cream or moisturizer on your skin can help soothe any red, irritated skin and help you avoid the urge to itch. Scratching the rash could open the wound, allow it to get dirty, and lead to an infection, which will take additional time to heal and possibly require additional medications. 

If you think you will be exposed to something that will cause an allergic skin rash and it cannot be avoided, you can take antihistamines (levocetirizine, fexofenadine, or loratadine) beforehand to help prevent symptoms. For instance, taking antihistamines before visiting your friend who has a cat or dog, can reduce the itching and rash from hives produced from contact with the pet’s dander.

Itchy Skin, Chronic Hives & Antihistamines

by Dr. Waverly Yang, PharmD, Curist Pharmacy Advisor

Curist delivers FDA-approved medicines to your door at half the price of traditional brands. We hope everyone stays safe and healthy during this time.

As someone who suffers from eczema, psoriasis, and chronic hives, I know intense itching can affect not just your skin, but your health and overall well being.  After years of experiencing symptoms as a patient and then studying them as a pharmacy student, I’ve finally learned how to manage my symptoms and ease off the itching.  Although what worked for me may not work for everyone, below are my top insights and tips for those of us managing itchy skin.

A regimen to manage pruritus (AKA, itchy skin) will depend on whether the condition is acute (temporary) or chronic (long-term).

Acute pruritus, which lasts less than six weeks, can have a variety of causes, including contact dermatitis (a reaction to something touching your skin like poison ivy), fungal or bacterial infections, insect bites, an allergic reaction to a food, medicine or other allergen, or even just dry skin. In more rare cases, the itching could be a symptom of internal issues or underlying mental stressors. Acute rashes are usually temporary and often easy to cure. 

Chronic pruritus, which lasts at least six weeks, may be caused by skin conditions (like eczema and psoriasis), sensitive or dry skin, and chronic hives.  These conditions are often difficult to cure and may require symptom management and avoiding triggers to minimize the intensity. 

If you develop a new rash or sudden itch persists for a few days, consult with your doctor or dermatologist to investigate the cause of the rash.  If you have chronic pruritus, then it will be particularly important to follow the tips below.

Hives, also known as urticaria, are itchy, red or skin-colored patches of slightly raised skin (welts) that often show up in batches due to an allergic reaction. As with pruritis, there can be acute and chronic hives with the latter lasting more than six weeks. It can be difficult to figure out what is triggering your skin, but potential triggers could include stress, pressure on the skin, or even sunlight. Although they may not be dangerous to your health, they can be irritating, make it difficult to sleep, and interfere with your life.

Every person is different, so it’s up to you to figure out what your skin triggers are. Triggers can include animals, plants, food, certain scents, hot water, as well as stress. Invisible triggers like stress and anxiety can affect your body’s nervous system and cause itching, burning, and hives. Be meticulous as you investigate your potential triggers.  Keep a log of the things you eat, how stressed you are, new products you’ve tried, and any other details that could help you figure out what puts your skin on the fritz. To narrow down the list of potential triggers, you might consider taking a skin allergy test. I balked when my allergist told me I had a soy allergy (I couldn’t imagine life without soy sauce!), but cutting soy out of my diet was the biggest factor in improving my skin.

It’s important to remove excess water from your skin. Excess moisture can cause irritation and create a breeding ground for bacteria and fungi.   When cooking, cleaning, or washing the dishes, make sure to wear gloves to protect your hands, and always moisturize after washing your hands, especially if you’re washing frequently.  If you’re perspiring, wipe off excess sweat with a towel and change out of your wet clothes as soon as you’re able. 

Whether you’re hearing this for the first time or the millionth time, it’s true. Dry skin is a common culprit of triggering scratch attacks. When the skin is dry, it’s prone to inflammation, irritation, and a loss in elasticity. Quench your skin’s thirst with a good, fragrance-free moisturizer. Using a “fragrance-free” product is critical because even unscented products can contain fragrances that irritate the skin. Brands like Aveeno, Eucerin, Cetaphil, and Vanicream have made excellent fragrance-free products.  The severity of your dry skin will determine whether you need a lotion or cream.  

• For mild to moderately dry skin: try a lotion as a moisturizer.  
• For very dry and flaky skin: try a cream for longer-lasting relief.   
• For intensely dry problem areas: consider thicker products for better penetration like Vaseline and Aquaphor, but make sure the area is clean and dry before applying to prevent fungal infections from occurring.  

Carry a travel-sized version of your favorite lotion with you at all times. I am guilty of forgetting to moisturize, simply because I don’t always have lotion or cream on hand. Make sure to keep lotion readily accessible after every hand wash or whenever you feel an itch coming on.  Remoisturize throughout the day.If your skin has an adverse reaction to any moisturizer, STOP using the product immediately.  This is a signal that one or more ingredients in the product may not be suitable for your skin, and we want to keep our skin happy.

Itching sensations occur when your skin’s nerve endings send signals to your spinal cord and brain, which will trigger your body’s reflexive response to scratch away those sensations.  Although the triggers for these signals may vary, they are usually mediated by naturally-produced chemicals, like histamine. Medications, like antihistamines, usually target this pathway and the chemicals involved to relieve the itching feeling.

Antihistamines have been a big help for me since it helps to calm down my chronic hives, in addition to reducing itchiness caused by my eczema and psoriasis. Common antihistamines are fexofenadine (brand Allegra), cetirizine (brand Zyrtec), loratadine (brand Claritin), and levocetirizine (brand Curist). For me, the best antihistamine has been cetirizine (brand Zyrtec) but everyone’s body is different so that may not work as well for you. I’d suggest trying each of the antihistamines until you can find the one that works best for you. If your itching is particularly bad at night, consider taking diphenhydramine (known as brand Benadryl), which will induce drowsiness to help you sleep as it alleviates your symptoms. 

If the antihistamine you’ve been taking seems to have lost its effectiveness, it might be time to change up your regimen. It’s not always clear whether the diminished effect is because your body has built up a tolerance or because your allergies may have intensified, but it’s worth trying a “drug holiday. ” Try taking a short break from your antihistamine, or try a different antihistamine altogether.

My chronic hives can be pretty stubborn, and, while antihistamines are a huge help, some flare-ups require a stronger approach. If antihistamines aren’t giving you enough relief, it’s best to see an allergist to talk about additional treatment options. They may recommend a combination of antihistamines or even prescribe other medications to manage your symptoms.

If you are experiencing short-term, mild itching, you can probably self-treat with an over-the-counter topical steroid, like hydrocortisone.  However, for skin conditions like eczema, psoriasis, and even chronic hives (especially for flare-ups), doctors may prescribe a more potent steroid cream than hydrocortisone. 

It’s important to understand that persistent use of steroid creams (without breaks) may lead to topical steroid dependence, which can sometimes lead to even worse flare-ups and other negative side effects.

For the longest time, I had to use my steroid cream every day because my eczema would flare up the very next day without it. My skin had developed a steroid dependence, and I would experience withdrawal effects whenever I stopped.  Always follow your doctor’s directions on using steroid creams and, when your symptoms are more manageable, consider tapering off the cream slowly and under your doctor’s supervision.

Living with itchy skin can be very irritating, but by paying attention to how your skin reacts, symptom management is definitely possible. Every person’s skin and body are different, but I hope this quick guide gives you a starting point to finding relief on your skin journey.

things to think about uMEDp

The article deals with the pathogenesis of pruritus, possible psycho-emotional problems and somatic triggers of pruritus. The advantages of second-generation antihistamines, in particular cetirizine, are described: in addition to blockade of h2-histamine receptors, the drug inhibits the migration of eosinophils in the focus of inflammation, suppresses the skin response to platelet-activating factor. The results of our own studies showing the effectiveness of cetirizine in dermatological diseases are presented. Namely: the maximum reduction in the intensity of itching already three hours after application during the first five days of therapy.

Fig. 1. Algorithm for diagnosing pruritus

Fig. 2. Distribution of patients by nosology

Fig. 3. Average subjective assessment of the intensity of itching after the use of the drug

Fig. 4. Dynamics of clinical manifestations

The skin makes up about 15% of the total human body weight and is the largest organ. Its most important function is protective.

The condition of the skin has a significant impact on a person’s self-esteem and the formation of interpersonal relationships.

Skin itching is an unpleasant subjective sensation that causes a desire to scratch. This symptom in the vast majority of cases causes discomfort, psycho-emotional stress and exhaustion. In addition, as a result of combing, the integrity of the skin is violated.

It should be noted that, despite the high prevalence of the symptom, it has not been sufficiently studied due to the difficulties of its adequate assessment and the lack of models for research.

Somatic triggers of pruritus

Generalized itching that occurs without concomitant manifestations on the skin can be due to various reasons – from skin xerosis to endocrinological pathologies or carcinoma. That is why in clinical practice one should not neglect the assessment of this important prognostic symptom.

Relatively benign etiological factors include drug allergic reactions, dry skin, scabies, and primary dermatological diseases. Most often, pruritus is observed with dry skin. In older patients, it occurs in 10–50% of cases [1]. Generalized pruritus occurs in 13% of patients with chronic renal failure and in 70–90% on hemodialysis [2]. Liver diseases accompanied by cholestasis (primary biliary cirrhosis of the liver, cholestasis caused by oral contraceptives, intrahepatic cholestasis during pregnancy, etc. ) also often cause pruritus [2].

Among the hematological diseases that cause itching are polycythemia, iron deficiency anemia, endocrine diseases – thyrotoxicosis and diabetes mellitus [3].

Itchy skin is a common clinical manifestation of AIDS and associated Kaposi’s sarcoma, opportunistic infections. Thus, itching with or without skin rashes is observed in 84% of AIDS patients, in 35.5% of patients with Kaposi’s sarcoma, which developed against the background of AIDS. AIDS-associated opportunistic infections are accompanied by itching in 100% of cases [4].

It has been established that pruritus can appear in malignant diseases. For example, with Hodgkin’s lymphoma, itching is observed in 10-25% of patients, it is characterized by high intensity and limited localization, more often in the lower part of the legs. In some cases, this symptom precedes the diagnosis of lymphoma and may serve as an indicator of a less favorable disease prognosis than fever or weight loss [4]. Adenocarcinomas and squamous cell carcinoma of various organs (stomach, pancreas, lungs, colon, brain, breast, prostate) are accompanied by itching on larger areas of the skin: on the legs, upper body and extensor surfaces of the arms. At the same time, there is a direct relationship between the presence of itching and the activity/recurrence of cancer [4].

Secondary skin itching is usually associated with taking drugs such as opium derivatives (cocaine, morphine, butorphanol), phenothiazines, tolbutamide, erythromycin, anabolic hormones, estrogens, progestins, testosterone, aspirin, quinidine and other antimalarial drugs, biologics ( monoclonal antibodies), vitamin B. In addition, it is known that itching can be a subclinical manifestation of hypersensitivity to any drug [5].

Since itching is observed not only in dermatological pathologies, it is advisable to conduct a thorough examination of patients (Fig. 1) and treat them taking into account the identified pathology.

Mechanisms of development and relief of pruritus

Hypotheses of the mechanisms of itch development were formulated on the basis of a study of the pathophysiology of pain, since pain and itch combine common molecular and neurophysiological mechanisms.

The sensation of itching and pain is the result of the activation of a network of free nerve endings in the dermal-epidermal zone. The trigger mechanism is the influence of internal or external thermal, mechanical, chemical stimuli or electrical stimulation. Skin nerve irritation can be mediated by several biological agents, including histamine, vasoactive peptides, enkephalins, substance P, prostaglandins.

It is believed that other, non-anatomical factors, such as psycho-emotional stress, individual subjective perception, the presence and intensity of other sensations and / or distractions, have a significant impact on the degree of itch sensitivity in different areas of the skin.

The nerve impulse that causes the sensation of itching, which has arisen under the influence of any of the listed factors, is transmitted along the same neural connection as pain impulses: from peripheral nerve endings to the dorsal horns of the spinal cord, through the anterior commissure, along the spinothalamic tract to the contralateral laminar nucleus of the thalamus. It is suggested that the thalamocortical tract of tertiary neurons acts as a “relay” for impulse transmission through the integration of the reticular activating system of the thalamus in several areas of the brain. In response, there is a desire to comb the skin, which is formed in the corticothalamic center and is realized in the form of a spinal reflex. After scratching, itching reappears after 15–25 minutes. However, in some cases, especially in patients with chronic dermatoses, the sensation of itching after scratching does not stop, which leads to excoriation.

Despite the fact that many etiological and pathogenetic factors contributing to the occurrence of itching are currently known, their study continues and new mechanisms are being discovered.

The mechanism by which itching is relieved by scratching has not been reliably established. Perhaps, during scratching, sensory impulses are formed that interrupt the neural arc responsible for the occurrence of sensation.

In addition to scratching, vibrations, injections into the itchy area, exposure to heat, cold, and ultraviolet radiation help to reduce itching [3].

Treatment

Therapeutic methods should be aimed primarily at eliminating pathogenetic factors.

Patients are shown sedatives (especially for intense chronic itching), emollients (to reduce skin dryness, which is both a cause and a consequence of itching), topical distractions (cold lotions, menthol-containing products, etc.), antihistamines, which in the vast majority of cases are first-line drugs.

There are two generations of antihistamines: sedatives (Suprastin, Tavegil, Diazolin, Diphenhydramine, Phencarol, Fenistil) and non-sedative/mildly sedatives (cetirizine, levocetirizine, loratadine, desloratadine, fexofenadine, ebastine, rupatadine).

It is important to note that, despite the need to take sedatives, it is better not to use first-generation antihistamines (which have a sedative effect in addition to the antihistamine). Firstly, sleep during their use is non-physiological (drugs inhibit the phase of REM sleep). Secondly, the multiple side effects characteristic of this group of drugs limit the possibility of their use in patients with comorbidities.

Therefore, it is better to use tranquilizers as sedatives, and when choosing antihistamines, preference should be given to second-generation blockers.

Cetirizine occupies a special place among them.

Cetirizine

Cetirizine inhibits the histamine-mediated early phase of the allergic reaction, prevents various physiological and pathophysiological effects of histamine, such as dilation and increased capillary permeability (development of edema, urticaria, redness), stimulation of sensitive nerve endings (itching, pain) and contraction of the smooth muscles of the respiratory and gastrointestinal tract.

In the late stage of an allergic reaction, cetirizine not only inhibits the release of histamine, but also the migration of eosinophils and other cells, thus attenuating the late allergic reaction. Reduces expression of adhesion molecules such as Intercellular Adhesion Molecule 1 (ICAM-1) and Vascular Cellular Adhesion Molecule 1 (VCAM-1), which are markers of allergic inflammation .

In addition, unlike other drugs used for skin manifestations of allergies, cetirizine not only blocks H ₁ -histamine receptors, but also suppresses the skin response to platelet-activating factor [6, 7]. This is confirmed by the results of numerous clinical comparative studies: due to the ability to accumulate in the skin, the drug relieves itching and hyperemia more effectively than such drugs as ebastine, epinastine, terfenadine, fexofenadine and loratadine [8–10].

Compared to other antihistamines, cetirizine has a low volume of distribution of 0.5 l/kg. This provides higher concentrations of the substance in the extracellular space, where the H ₁ histamine receptors are located. Thus, their full employment and the highest antihistamine effect are ensured [11]. Another feature of the drug is its high ability to penetrate the skin. 24 hours after taking a single dose of cetirizine, the concentration in the skin is equal to or even slightly higher than the concentration in the blood. The advantage of cetirizine is the steroid-sparing effect: with the simultaneous administration of cetirizine and inhaled glucocorticosteroids in patients with bronchial asthma, the dose of the latter may be reduced or not increased, despite contact with the allergen.

Among cetirizines, Cetrin occupies a special place. In the study of E.E. Nekrasov et al. in patients with chronic urticaria, Cetrin showed the highest efficacy among other cetirizine generics and the best results in terms of pharmacoeconomics [12].

Application experience

We observed 75 patients aged 18 to 76 years (34 men and 41 women) with diagnoses of “atopic dermatitis”, “allergic dermatitis”, “chronic eczema in the acute stage”, “lichen planus”, “toxidermia” ( Fig. 2).

All patients received topical and systemic therapy, which included the antihistamine drug Cetrin (cetirizine) at a dose of 10 mg once a day at night. The duration of therapy is from 14 to 21 days, depending on the diagnosis.

Patients assessed the effectiveness of itching relief according to a point system: 0 points – no itching, 1 point – mild itching (present, but does not bother), 2 points – moderate (it bothers, but does not interfere with daily activity and / or sleep), 3 points – severe / intense itching (disturbs and interferes with daily activity and / or sleep).

The maximum decrease in the intensity of itching was observed already three hours after taking the drug in the first five days (Fig. 3).

Subsequently, a decrease in itching or its absence was noted by the tenth day of therapy with a simultaneous decrease in the clinical manifestations of diseases (Fig. 4).

The results obtained demonstrate the high efficiency of Cetrin (cetirizine) in the treatment of chronic and acute dermatoses. Cetrin (cetirizine) has a pronounced antipruritic effect, and also reduces other clinical manifestations of allergic dermatosis (infiltration, erythema). In addition, as a symptomatic therapy, the drug can also be used for somatic diseases.

Antihistamines in solving the problem of pruritus

Itching is one of the most common symptoms of most skin diseases, and can also be a leading manifestation of a number of somatic disorders (infections, metabolic disorders, etc.). Patients describe itching as a burning, tingling, or uncharacteristic sensation that can vary in intensity, localized, or generalized. Persistent, chronic itching in the vast majority of cases leads to a deterioration in the quality of life as a result of sleep disorders, disability and difficulty in performing daily household chores, the development of depression up to suicide.

There is no single, generally accepted classification of pruritus, but it is divided into pruritus, which occurs when the endings of sensitive skin nerves are irritated, neuropathic, which appears when the nerve endings are damaged, neurogenic, which develops as a result of the central effect of pruritus mediators, and psychogenic. This classification is very arbitrary, since a number of diseases accompanied by itching (for example, atopic dermatitis, hepatic cholestasis) fall into several categories. However, it is quite convenient to use it in everyday clinical practice [1].

Itching can be caused by mechanical irritation – light touch, pressure, vibration, skin contact with textile fibers. Thermal and electrical stimuli can also contribute to this symptom. A common cause of itching that occurs in pathological conditions is exposure to endogenous chemicals formed and accumulated in the skin or affecting the central nervous system.

The mechanisms of the development of this symptom have been comprehensively studied over the past 60 years, but now there are new, additional data on the pathogenesis of pruritus [2, 3].

Itching is transmitted mainly along unmyelinated C- and A-fibers as a result of exposure to their free nerve endings at the border of the epidermis and dermis of various external and internal stimuli. Histamine is the most important mediator involved in the development of itching. However, it is not the only pruritogenic substance. Skin itching can also be caused by other biogenic amines – serotonin and acetylcholine, proteases and kinins (tryptase, chymase, kallikrein, bradykinin), cytokines (interleukin 1, 2, etc.), neuropeptides (substance P, endothelium, neurotensin, etc.), opioids (methenkephalin, leuenkephalin, β-endorphin), receptors for which are located at the ends of the peripheral sensory nerves of the skin. Most of these substances are produced during the development of inflammation that accompanies most pruritic dermatoses.

Prolonged, chronic stimulation of pruriceptors not only causes itching, but also activates the intensity of the corresponding impulse at the spinal level, which leads to the spread of itching beyond the primary focus and an increase in this symptom. Thus, in a chronic inflammatory process in the skin, another pathological circle can form in the form of “central sensitization to itching”. Pain, which is an integral part of the inflammatory process, can also aggravate or mimic the clinical manifestations of itching, which can also be interpreted as itching [4].

Regardless of the original cause of itching, this symptom may increase in proportion to the increase in the intensity of inflammation or dryness of the skin and its overheating due to various causes. An important role in the intensification of itching is played by psycho-emotional stress, to the development of which, in turn, long-term itching predisposes.

Thus, despite the variety of causes and mechanisms that cause itching, the complexity of their interaction in the formation of this symptom, there are specific molecular targets, the impact on which allows not only to stop it, but also to influence the chains of pathological reactions that are both the cause and a consequence of inflammation.

Antihistamines are widely used for the treatment of various diseases of an allergic nature, as well as for the symptomatic relief of itching. The drugs of this group also have anti-inflammatory activity due to the ability to inhibit the nuclear factor kB, which is a transcription factor and a mediator of immune and inflammatory reactions. Normally, it is at rest on the surface of the cell membrane, but when activated by histamine or tumor necrosis factor-α, it moves to the cell nucleus, where it stimulates transcription of messenger RNA for further synthesis of pro-inflammatory cytokines and adhesive proteins.

Desloratadine is the primary active metabolite of loratadine, a selective histamine H1 receptor antagonist that inhibits the release of histamine and C4 leukotriene from mast cells. Refers to antihistamines of the III generation. The drug has an antiallergic, antipruritic effect, effectively stops the exudation that accompanies a number of allergic diseases, prevents the development and facilitates the course of allergic reactions.

Desloratadine is distinguished by a rapid onset (15-30 minutes after administration), high efficacy and duration of action (within 24 hours), as well as the absence of sedative and cardiotoxic effects characteristic of previous generation antihistamines. Desloratadine is metabolized mainly by glucuronidation to form the 3-OH form. The pharmacokinetics of this drug is linear and proportional to the administered dose. The half-life is 21-24 hours, which allows you to prescribe desloratadine once a day [5-7].

The standard therapeutic dose of desloratadine is 5 mg/day, but this dose is not enough to relieve itching, one of the leading symptoms of a number of skin diseases. Currently, there are publications that testify to the safety and efficacy of a 2- and even 4-fold increase in the standard dose of the drug [8, 9].

On the basis of City Clinical Hospital No. 14 named after. V.G. Korolenko, we conducted a study, the purpose of which was to evaluate the effectiveness of Lordestin (desloratadine) in the treatment of patients with acute and chronic non-infectious skin diseases.

The study included 60 patients (40 women, 20 men) aged 18-70 years (mean age 48.0±7.2 years) suffering from chronic eczema, atopic dermatitis, lichen planus in the acute stage, allergic dermatitis, toxidermia (Fig. 1). Figure 1. Patients with acute and chronic non-infectious dermatoses.

Patients participating in this study received combined topical and systemic therapy. As an antihistamine, all patients took Lordestin 1 tablet (5 mg) once a day. The observation period was 20 days. The effectiveness of therapy was assessed on the 10th and 20th days.

In our study, no undesirable side effects were observed in any patient during the use of Lordestin .

Prior to the start of complex treatment with Lordestin , 24 patients had clinical manifestations of the disease on the skin, which, when filling out individual registration cards, were rated as “severely pronounced”, in 36 patients – as “moderately pronounced”. The severity of itching in 32 patients was assessed as “severe”, in 28 – as “moderate”.

After the end of therapy, the severity of clinical manifestations of the disease on the skin in all patients decreased and in 32 patients it was assessed as “moderate”, in 20 – as “weak”. In 8 patients, there were no clinical manifestations on the skin. The severity of itching after the end of therapy also decreased: in 24 patients it was assessed as “moderate”, in 24 patients it was “mild”, in 12 patients itching was not noted (Fig. 2 and 3). Figure 2. Changes in the severity of clinical manifestations of the disease. Figure 3. Changes in the severity of itching.

Dermatological index of quality of life before complex treatment with Lordestin averaged 19.8 ± 4.1 points out of 30 maximum possible, indicating a negative impact of skin disease on the patient’s quality of life. After the end of treatment, the quality of life of patients improved, and the dermatological index of quality of life averaged 9.7±3.6 points.

Prior to complex treatment with Lordestin , the severity of pruritus, assessed by patients using a visual analogue scale, averaged 7.3, after the end of therapy – 2.4 (Fig. 4). Figure 4. Itching analog scale.