What are the common triggers for contact dermatitis. How can you identify the symptoms of this skin condition. What are the most effective treatments for alleviating contact dermatitis discomfort. How does contact dermatitis differ from other skin allergies.

Understanding Contact Dermatitis: A Common Skin Allergy

Contact dermatitis is a widespread skin condition that occurs when the skin comes into contact with an irritant or allergen. This inflammatory reaction can cause discomfort and distress for those affected. By understanding its causes, symptoms, and treatments, individuals can better manage this condition and find relief.

Types of Contact Dermatitis

There are two main types of contact dermatitis:

• Irritant contact dermatitis: Caused by direct skin damage from exposure to harsh substances
• Allergic contact dermatitis: Triggered by an immune system response to a specific allergen

Both types can present similar symptoms, but their underlying mechanisms differ.

Common Triggers and Causes of Contact Dermatitis

Contact dermatitis can be triggered by a wide range of substances. Identifying these triggers is crucial for effective management and prevention.

Irritant Contact Dermatitis Triggers

• Soaps and detergents
• Cleaning products
• Solvents and chemicals
• Prolonged water exposure
• Friction from rough materials

Allergic Contact Dermatitis Triggers

• Nickel and other metals in jewelry
• Latex
• Fragrances in cosmetics and personal care products
• Certain plants (e.g., poison ivy)
• Topical medications

Can contact dermatitis be caused by food allergies? While food allergies typically manifest in other ways, they can occasionally cause skin reactions. However, true contact dermatitis from food is rare and usually occurs from direct skin contact rather than ingestion.

Recognizing the Symptoms of Contact Dermatitis

The symptoms of contact dermatitis can vary in severity and presentation, but typically include:

• Redness and inflammation
• Itching and burning sensation
• Dry, cracked, or scaly skin
• Swelling
• Blisters or bumps
• Oozing or crusting in severe cases

How quickly do contact dermatitis symptoms appear? The onset of symptoms can vary depending on the type of dermatitis and the individual’s sensitivity. Irritant contact dermatitis often develops quickly, sometimes within minutes of exposure. Allergic contact dermatitis may take 24 to 72 hours to manifest after exposure to the allergen.

Diagnosing Contact Dermatitis: When to See a Professional

While mild cases of contact dermatitis can often be managed at home, it’s important to know when to seek medical attention.

Reasons to Consult a Healthcare Provider

• Severe or widespread rash
• Symptoms that don’t improve with home treatment
• Signs of infection (increased pain, warmth, or pus)
• Rash that interferes with daily activities or sleep
• Uncertainty about the cause of the rash

How do healthcare providers diagnose contact dermatitis? Diagnosis typically involves a thorough examination of the affected area and a detailed medical history. In some cases, patch testing may be recommended to identify specific allergens.

Effective Treatments for Contact Dermatitis Relief

Treatment for contact dermatitis focuses on relieving symptoms and preventing future flare-ups. A combination of self-care measures and medical interventions can be effective.

Self-Care Strategies

• Avoid scratching to prevent further irritation and infection
• Apply cool, wet compresses to soothe inflamed skin
• Use gentle, fragrance-free moisturizers to keep skin hydrated
• Take lukewarm baths with colloidal oatmeal to relieve itching
• Wear soft, breathable clothing to minimize irritation

Medical Treatments

• Topical corticosteroids to reduce inflammation
• Oral antihistamines to alleviate itching
• Topical calcineurin inhibitors for chronic cases
• Oral corticosteroids for severe, widespread reactions
• Antibiotics if secondary infection occurs

What is the most effective way to treat contact dermatitis? The most effective treatment often involves a combination of avoiding triggers, proper skin care, and appropriate medications as recommended by a healthcare provider. Personalized treatment plans yield the best results.

Prevention Strategies: Minimizing Contact Dermatitis Risks

Preventing contact dermatitis involves identifying and avoiding triggers, as well as implementing protective measures.

Key Prevention Tips

• Identify and avoid known allergens and irritants
• Use protective gloves when handling potential irritants
• Apply barrier creams before exposure to irritants
• Choose hypoallergenic personal care products
• Patch test new products before widespread use
• Maintain good skin hygiene and moisturization

Is it possible to completely prevent contact dermatitis? While complete prevention may not always be possible, especially for those with sensitive skin, these strategies can significantly reduce the risk and frequency of flare-ups.

Differentiating Contact Dermatitis from Other Skin Conditions

Contact dermatitis can sometimes be confused with other skin conditions due to similar symptoms. Understanding the differences is crucial for proper treatment.

Common Skin Conditions Often Mistaken for Contact Dermatitis

• Atopic dermatitis (eczema)
• Psoriasis
• Hives (urticaria)
• Fungal infections
• Rosacea

How can you tell the difference between contact dermatitis and other skin conditions? The key lies in the pattern and timing of symptoms. Contact dermatitis typically occurs in areas that have come into direct contact with an irritant or allergen, while conditions like atopic dermatitis often have a more generalized distribution. Additionally, the rapid onset of symptoms after exposure is characteristic of contact dermatitis.

Living with Contact Dermatitis: Long-Term Management and Quality of Life

For many individuals, contact dermatitis is a chronic condition that requires ongoing management. Developing strategies for long-term care can significantly improve quality of life.

Tips for Long-Term Management

• Keep a symptom diary to identify patterns and triggers
• Develop a consistent skincare routine
• Communicate with employers about workplace accommodations if needed
• Stay informed about new treatment options
• Join support groups or online communities for shared experiences and advice

Can contact dermatitis have a significant impact on quality of life? Yes, chronic contact dermatitis can affect various aspects of life, including work, social interactions, and self-esteem. However, with proper management and support, most individuals can effectively control their symptoms and maintain a high quality of life.

Emerging Research and Future Directions in Contact Dermatitis Treatment

The field of dermatology is continually evolving, with new research offering hope for improved treatments and management strategies for contact dermatitis.

Promising Areas of Research

• Novel barrier repair therapies
• Targeted immunomodulators
• Microbiome-based treatments
• Advanced diagnostic techniques for allergen identification
• Personalized medicine approaches

What new treatments for contact dermatitis are on the horizon? While specific treatments are still in development, researchers are exploring various avenues, including biologics that target specific inflammatory pathways and innovative topical formulations that enhance skin barrier function. These advancements hold promise for more effective and personalized treatments in the future.

Contact dermatitis, while often uncomfortable and sometimes challenging to manage, is a condition that can be effectively controlled with the right approach. By understanding its causes, recognizing symptoms, and implementing appropriate treatment and prevention strategies, individuals can minimize its impact on their daily lives. As research continues to advance, the outlook for those affected by contact dermatitis continues to improve, offering hope for even better management options in the years to come.

Skin Allergies | Causes, Symptoms & Treatment

What does a skin allergy look like?

There are several different types of skin allergy reactions that allergists treat.

Eczema (also commonly called  atopic dermatitis) typically results in dry, sensitive skin. You may experience red itchy patches. Eczema can come and go over time, and flare-ups may crack, ooze, and itch severely. It is very itchy and can vary in severity from mild (just dry skin ) to severe (red, scaly, thick, fissured and oozing skin)

Hives (also known as urticaria) are raised itchy bumps. Typically hives appear reddish, and will “blanch” (or turn white) in the center when pressed.

Contact dermatitis is typically caused by exposure to an allergen or irritant. If you have red itchy bumps on your skin, especially at the site of contact with some potential irritant or allergen, you may be experiencing contact dermatitis.

If you suspect you have any of these conditions, your allergist can conduct an examination and do testing to help determine the cause of your skin reaction and can recommend treatment to help relieve your symptoms.

How can I relieve the itching from my skin rash?

Avoid scratching! Scratching your rash or hives can create more irritation and can lead to infection. Frequent baths followed immediately with adequate moisturization may help ease your discomfort.

Allergists are specially trained to help treat your condition. Your allergist may prescribe a cream or oral medication to help alleviate your discomfort. Antihistamines and moisturizing ointments can also help ease irritation and dryness. Recently, new medications have been approved, including an ointment for mild to moderate atopic dermatitis and a biologic for moderate to severe atopic dermatitis. You can discuss these options with your allergist.

I haven’t changed anything about my usual routine – what could be causing my skin rash or hives?

There are many possible causes for your skin rash. Some types of rashes are caused by allergies, others may be caused by infections, skin conditions such as eczema or rosacea, or even just dry or damaged skin. Your allergist can help diagnose the cause of your symptoms and prescribe treatment to help you take control and find relief.

Should I stay out of the sun until my rash or hives are gone?

If your skin is already irritated or sensitive, exposure to UV rays and possible sunburn could cause you more discomfort. Take control of your condition by covering up and minimizing your time in direct sunlight.

In addition, some types of skin rash can be caused by the sun. Photoallergic contact dermatitis occurs when your skin has a reaction to an irritant or allergen after exposure to the sun. Cosmetics, sunscreen, shaving lotion, and perfume can trigger this kind of reaction.

Consult with your allergist to determine the cause of your skin reaction and the best course of treatment.

Could my skin reaction be caused by a food allergy?

Yes! A reaction to a food allergen can cause you to have a skin reaction like hives.

There are many possible causes for hives and rashes, so consult with your allergist to determine the cause of your symptoms and the best course of treatment.

Latex Allergy | Causes, Symptoms & Treatment

Triggers and Symptoms

What triggers the allergic reaction to latex?

When people with latex allergy come into direct contact with latex, an allergic reaction may follow. Common examples include:

• A medical or dental procedure conducted by health care workers wearing natural rubber latex gloves
• Blowing up a rubber balloon

What are latex allergy symptoms?

In most cases, latex allergy develops after many previous exposures to latex. Latex allergy symptoms may include hives, itching, stuffy or runny nose. It can cause asthma symptoms of wheezing, chest tightness and difficulty breathing. Symptoms begin within minutes after exposure to latex containing products. The most severe latex allergy can result in anaphylaxis, a serious allergic reaction involving severe breathing difficulty and/or fall in blood pressure (shock).

Allergic skin problems can occur following direct contact with allergic latex proteins in latex glove products. Symptoms may include immediate itching, redness and swelling of skin that touched the item containing latex. These and other latex allergic reactions are less common now. Many hospitals or doctors’ offices have switched to non-latex gloves or low protein latex gloves.

A second type of skin allergy called “allergic contact dermatitis” may be caused by chemicals used to manufacture rubber gloves. This dermatitis is recognized by the eczema and blisters on the back of the hands. It resembles a poison ivy rash, and begins 1 to 3 days after wearing rubber gloves.

Direct physical contact with latex products is not needed to trigger an allergic reaction. Anaphylaxis and severe asthmatic reactions have been caused by inhaling latex proteins in the air resulting from the powder in the latex glove.

What foods are potential problems for people with latex allergy?

If you have latex allergy you also can have food allergies. The foods most likely to cause this problem include: apple, avocado, banana, carrot, celery, chestnut, kiwi, melons, papaya, raw potato and tomato.

Management and Treatment

How is latex allergy diagnosed?

Latex allergy is diagnosed by an allergy blood test.

How is latex allergy treated?

The best treatment for latex allergy is avoidance. If you have severe latex allergy reaction you should:

• Wear medical alert identification
• Carry an Epinephrine has been produced synthetically as a drug since 1900. It remains the drug of choice for treatment of anaphylaxis."}" data-sheets-userformat="{"2":8963,"3":{"1":0},"4":[null,2,16777215],"11":4,"12":0,"16":10}">Epinephrine is a naturally occurring hormone, also called adrenaline. It is one of two chemicals (the other is norepinephrine) released by the adrenal gland. Epinephrine increases the speed and force of heart beats and thereby the work that can be done by the heart. It dilates the airways to improve breathing and narrows blood vessels in the skin and intestine so that an increased flow of blood reaches the muscles and allows them to cope with the demands of exercise. Epinephrine has been produced synthetically as a drug since 1900. It remains the drug of choice for treatment of anaphylaxis.</span>” rel=”tooltip”>epinephrine (adrenaline) auto-injector for emergency treatment

Health care workers with a history of latex sensitivity who must wear gloves should stop wearing latex gloves. Their co-workers should also not use latex gloves, but rather switch to synthetic gloves.

Patients with latex allergy are at risk of asthma on exposure to latex-containing aerosols. They should try to avoid areas where powdered latex gloves or other latex products are used.

How can latex allergy be prevented?

If you have latex allergy you should avoid direct contact with all products and devices that contain latex. Also avoid food that causes an allergic reaction. Latex allergy problems during dental, medical or surgical procedures can be prevented by warning health care providers about latex allergy before any test or treatment. Latex allergic people can receive medical or dental care in a latex-safe area. Hospitals and clinics that use only low protein latex gloves and non-latex gloves have experienced dramatic declines in new cases of latex allergy.

Allergists can provide latex-allergic people with information and assistance to help them avoid products which may contain latex. The American Latex Allergy Association also has additional information.

With the right treatment plan, you’ll understand how to manage your allergies, so you can be in control.

Allergy ointment. How to eliminate an allergic rash – an article on the site Aptechestvo, Nizhny Novgorod

An inadequate reaction of the body to contact with factors of the external or internal environment causes the development of allergies. If the human immune system has reacted incorrectly to irritants, a cough, choking, an allergic rash, and other non-standard reactions appear. It is they who most often become the first symptom of malfunctions in the immune system.

Causes

Skin allergies often manifest as a rash. These are small blisters, flaky spots, itchy redness, which are visualized on the face, head, body. The affected areas can be pinpoint or affect large areas. More often defects appear in children, less often in adults.

Skin allergic rash, causes and provoking factors:

• genetic predisposition;

• contact with dust, chemicals, plant pollen;

• ingestion of food and drugs to which a person has a certain sensitivity;

• parasite metabolites;

• sun and cold;

• animal hair;

• cosmetics, etc.

In many people, the reaction occurs as a result of metal contact (nickel, silver), latex, insect bites, use of perfume, wearing natural wool, or contact with domestic/wild animals.

Until now, the exact causes of the disease are being studied, but scientists are confident that the genetic predisposition or sensitivity of the immune system to certain substances, as well as a violation of the properties and functions of the epidermis in infancy, underlie the development of pathology.

Skin allergies, symptoms

Depending on the nature of the lesions and symptoms, there are different types of allergies on the body. It is important to correctly identify the disease in order to prescribe effective treatment and eliminate the causes.

Dermatitis

Allocate contact, atopic and photodermatitis. It is manifested by flaky spots, blisters, accompanied by itching, swelling and swelling. Occurs as an immediate reaction to a contract with an allergen or after a few hours / days with a food irritant. In a child of the first year of life, such symptoms indicate intolerance to milk protein. Photodermatitis – the reaction of the epidermis to the sun’s rays with a special susceptibility or climate change. An allergic rash on the face can also be the result of dermatitis.

Eczema

A disease of a neuro-allergic nature, which is complex in terms of the mechanism of development. Symptoms:

• extensive redness;

• multiple small vesicles;

• dryness or weeping;

• crust formation.

It often occurs in adults who are regularly exposed to stress. The affected areas are the folds of the limbs, folds on the neck and body.

Urticaria

By the nature of the manifestation, it resembles a burn after contact with nettle leaves. Red spots and blisters appear on the body that itch. Allergic rash urticaria is the result of an instantaneous response of the body to food, medicine, heat, physical stress, insect bite. It lasts from several hours to several days, it can be chronic.

Quincke’s edema

The most severe form of allergy. Affects soft tissues and can pass to the mucous membranes. Edema can be determined by swelling and swelling of the face, lips, neck, eyelids. Develops rapidly as a response to medications, certain foods (eggs, seafood, nuts), latex contract, chemicals, wasp stings, bee stings, etc. Requires rapid emergency medical attention due to the high risk of suffocation as a result of laryngeal edema.

Diagnostics

In addition to a visual examination and analysis of the patient’s complaints, the doctor usually prescribes the following examinations:

• general and biochemical blood test;

• blood test for specific IgE antibodies;

• scarification tests.

Diagnosis may also include a review of the diet, especially if the problem is in a young child.

Treatment

An integrated approach to the disease is the basis for effective treatment of allergic manifestations on the skin. The main thing is to identify the cause, prevent recurrence and relieve unpleasant symptoms in the acute period. To do this, use oral antihistamines, corticosteroids, creams, lotions and ointments for external use.

Ointments are different according to their functions:

The most effective for quickly eliminating itching and redness are hormonal (for example, Advantan). They are used in doses, in the acute phase, as directed by a doctor.

Children and adults with atopic dermatitis are shown special caring ointments (Topicrem), which help retain moisture, help restore the integrity of the skin during scratching and damage, relieve itching, inflammation, restore local microflora, and increase immunity.

A good effect in the treatment is given by antihistamines (for example, Fenistil). They are designed to block histamine h2 receptors, which helps to reduce the manifestations of itching, inflammation and redness for the next few hours.

Ointments with D-panthenol (Bepanten) also alleviate the course of the disease and are considered the safest drugs that can be used on the body and face. Shown as an additional remedy for diseases of moderate severity and as the main one for mild allergies.

If a fungal or bacterial infection is suspected or diagnosed, combined ointments, for example, Triderm, give an excellent therapeutic effect. They contain broad-spectrum antibiotics, antifungal components, antipruritic, anti-inflammatory and anti-allergic. The application is shown in courses, the effect comes quickly.

Ointments for the treatment of allergies are one of the most effective means for relieving unpleasant symptoms – itching and burning. In addition, they prevent skin damage, promote tissue repair, and have a caring effect. They can be both the main and auxiliary means of treating a rash.

Allergic rash (Urticaria; urticarial rash) – Ministry of Health of the PMR

Allergic rash

(Urticaria; urticarial rash)

Allergic rash is a red, itchy, slightly raised swelling. Itching may be severe. An allergic rash may have well-defined borders and a pale area in the center. As a rule, hives eruptions come and go. One nodule may persist for several hours, then disappear, and later another may appear elsewhere. After the nodule disappears, the skin usually looks completely normal. The swelling is caused by the release of chemicals (such as histamine) from mast cells in the skin, which cause fluid to temporarily leak from small blood vessels.

Angioedema

Allergic rash can develop with Quincke’s edema, which, like an allergic rash, is accompanied by swelling. However, the swelling caused by angioedema is under the skin, not on its surface. Sometimes Quincke’s edema affects the face, lips, throat, tongue, and airways. It can be life-threatening if the swelling interferes with breathing.

Causes of allergic rash

Urticaria and Quincke’s edema are common allergic reactions.

Urticaria can be caused by inhaling, consuming, squirting, or touching certain chemicals. These chemicals may be present in the environment, food, drugs, insects, plants, or other sources. For most people, they are harmless. However, if people are sensitive to them, these chemicals (called triggers or allergens) can trigger an allergic reaction. This means that the immune system reacts to chemicals.

However, urticaria is not always part of an allergic reaction. For example, it can occur as a result of autoimmune diseases. In these diseases, dysfunction of the immune system causes the body’s own tissues to be misrecognised as foreign and attacked. In addition, some drugs directly cause hives without causing an allergic reaction. Emotional stress and certain physical stimuli (such as heat or light) can trigger hives for reasons that are not well understood.

Urticaria usually lasts less than 6 weeks and is classified as acute. If the urticaria lasts more than 6 weeks, then it is classified as chronic.

Acute urticaria most commonly caused by:

Allergic reactions are often caused by foods, particularly eggs, fish, shellfish, nuts and fruits, or insect bites. Eating even small amounts of certain foods can suddenly cause hives. But when eating other foods (for example, strawberries), an allergic reaction occurs only after eating them in large quantities. Many medications, especially antibiotics, can cause hives. Immediate allergic reactions can also occur when a substance comes into direct contact with the skin (such as latex), after an insect bite, or as a reaction to a substance that is inhaled into the lungs or through the nose.

Non-allergic causes of allergic rashes include infections, certain drugs, certain physical stimuli (such as pressure or cold), some emotional stimuli (such as stress), and certain dietary supplements.

Although acute urticaria usually has specific causes, in half of the cases the cause cannot be identified.

Chronic urticaria most commonly caused by:

Sometimes the cause is easily overlooked, such as when people consistently consume a food that is not known to be the cause of the reaction (such as a preservative or coloring in foods or penicillin in milk). Often, despite best efforts, the cause remains unidentified.

Chronic urticaria can last from several months to several years, sometimes disappearing for no apparent reason.

Evaluation of allergic rash

Not every episode of urticaria requires immediate medical attention. The following information can help you decide if you need to see a doctor and what to expect when you see a doctor.

Warning signs

Some symptoms and characteristics are cause for concern:

• Swelling of the face, lips, throat, tongue or airways (angioedema)

• Difficulty breathing, including wheezing

• Urticaria that is intensely colored, with open sores, or lasting more than 48 hours

• Fever, swollen lymph nodes, jaundice, weight loss and other symptoms of a general (systemic) illness

When to see a doctor

Call an ambulance if:

Call the emergency room or doctor’s office as soon as possible if:

• Symptoms are severe.

• The person feels increasing weakness or dizziness, or has a severe fever or chills.

• The person develops vomiting or abdominal pain or diarrhea.

Seek medical attention if:

• Bee sting causes urticaria (for treatment advice if another bee sting occurs).

• The person has other symptoms such as fever, joint pain, weight loss, swollen lymph nodes, or night sweats.

• Urticaria recurs without exposure to a provocative factor.

• Symptoms persist for more than 2 days.

If a child has urticaria that comes on suddenly, disappears quickly, and does not recur, a medical examination is usually not required. The cause is usually a viral infection.

What the doctor does

Doctors first ask questions about symptoms and medical history. Then they do a physical examination. Typically, a history and physical examination can identify a possible cause and determine what tests are needed.

Doctors ask the person to describe in detail each episode of hives and any other symptoms (eg, itching, difficulty breathing, or swelling of the face and tongue) that have occurred. They ask about the person’s activities before and during the episode and possible exposure to substances that can cause allergic reactions, including medications they take. The person is also asked about specific symptoms that might indicate a cause, previous allergic reactions, and recent travel.

The precipitating factor cannot always be determined from the medical history (often because the precipitating factor is something that may have been transferred before).

During a physical examination, doctors first check to see if the patient has swelling of the lips, tongue, throat, or airways. In the presence of edema, treatment is started immediately. Doctors then pay attention to what the hives look like, determine which parts of the body are affected, and check for other symptoms that may help confirm the diagnosis. Doctors can use a variety of physical stimuli to see if they can trigger hives. For example, they may apply light pressure, heat and cold to the skin, or stroke the skin.

Testing

Generally, testing is not required for a single episode of urticaria unless symptoms indicate a specific disorder that requires treatment (eg, some infections). However, if the urticaria has unusual characteristics, recurs, or persists, investigations are usually done.

Tests typically include a complete blood count and blood tests to measure electrolytes, sugar (glucose), and thyroid-stimulating hormone levels and determine how well your kidneys and liver are functioning. Skin testing, such as a skin prick test, is done by an allergist (a doctor who specializes in allergic conditions) to identify specific allergens. Imaging studies and other blood tests are performed based on the results of the medical history and physical examination. If the results suggest that the cause is a disease that affects the whole body, then a thorough examination is necessary to identify it.

Skin biopsy is performed if the diagnosis is unclear or if the rash persists for more than 48 hours.

Allergic rash treatment

• Avoidance of triggers

• Remedies for itching

• Medicinal preparations

Urticaria often resolves without intervention in a day or two. If the cause is obvious, or if a doctor identifies a cause, people should avoid it if possible. If the cause is not obvious, people should stop taking all non-essential medications until the hives resolve.

Symptoms can be relieved by bathing and showering with cool water only, avoiding scratching and wearing loose clothing.

Medicines

antihistamines taken by mouth are used to treat allergic rashes. These drugs partially relieve itching and reduce swelling. To achieve the effect, they should be taken regularly, and not as needed. Some antihistamines, including cetirizine, diphenhydramine, and loratadine, are available without a prescription. Diphenhydramine is the oldest drug that is more likely to cause drowsiness than the other two. Other antihistamines include desloratidine, fexofenadine, hydroxyzine, and levocetirizine. Creams and lotions containing antihistamines are generally not used because they can make the skin more sensitive and itch more

If symptoms are severe and other treatments fail, use oral corticosteroids (such as prednisone). They are taken for the shortest possible period of time. When taken by mouth for more than 3 to 4 weeks, corticosteroids cause many, including sometimes serious, unwanted effects (see Corticosteroid Uses and Side Effects). Corticosteroid creams do not help.

People admitted to the hospital with severe reactions or angioedema are given epinephrine . People with these severe reactions should have an epinephrine self-injection pen (epinephrine self-injection syringe) and should use it immediately if a reaction occurs.

About half of people with chronic urticaria go away without treatment within 2 years. In some adults, the antidepressant doxepin, which is also a powerful antihistamine, helps relieve chronic hives. Omalizumab, a monoclonal antibody, can be used in people with chronic allergic rashes that reappear despite other treatments.

Essential information for older people: Allergic rash

Older people are more likely to develop adverse effects when they take older antihistamines (eg, hydroxyzine and diphenhydramine). In addition to drowsiness, these drugs can cause confusion and delirium, and can also cause difficulty starting and passing urine. Generally, older people should not take these drugs to relieve hives.

KEY POINTS

• Urticaria may or may not be an allergic reaction.

• If urticaria has lasted less than 6 weeks, the cause is usually an allergic reaction to a specific substance, an acute infection, or a non-allergic reaction to a specific substance.

• If the urticaria has lasted 6 weeks or more, the cause usually cannot be identified (idiopathic) or the cause is an autoimmune disease.