What skin conditions can cause red, scaly patches or rings on the skin that resemble ringworm? Explore the different causes, from pityriasis rosea to contact dermatitis and nummular eczema.

Pityriasis Rosea: A Common, Self-Resolving Rash

Pityriasis rosea is a common, mild skin rash that may last for 6–8 weeks and often clears up on its own. The initial signs of infection include headache, fever, and cold-like symptoms. Soon after, a single scaly patch, about 2–10 centimeters (cm) in size, forms on the torso or neck. When the first patch appears, it can be mistaken for ringworm. As the condition runs its course, the rash spreads out into larger blotches.

The rash is not painful but may be itchy. In those with darker skin tones, it may appear gray, dark brown, or black and can cause flat dark spots lasting several months. In those with lighter skin tones, it may appear pink or red but rarely forms scars. The cause of pityriasis rosea is most likely the cold sore virus, but the rash is not contagious and cannot spread to others through physical contact. Pityriasis rosea can also occur a couple of weeks after a COVID-19 infection.

Contact Dermatitis: Skin Irritation from Allergens or Irritants

Contact dermatitis is a form of eczema that results from something coming into contact with the skin. As contact dermatitis can cause patches of thickened, scaly skin, it can be confused with ringworm. The patches may appear dark brown, purple, or gray on darker skin tones, while they usually appear bright red on lighter skin tones.

A person with contact dermatitis may be allergic to certain metals, such as nickel or cobalt, ingredients in cosmetics or soaps, or materials such as latex. “Contact dermatitis” can also describe skin irritations such as diaper rash or cracked skin after too much handwashing or dishwashing. In severe cases, the area may bleed or ooze.

Nummular Eczema: Coin-Shaped Patches of Itchy Skin

Nummular eczema, also known as discoid eczema, is a disorder that causes coin-shaped patches of itchy, swollen skin to appear. This type of eczema occurs mainly on hands, arms, or legs and sometimes on the trunk.

Ringworm and nummular eczema both look similar because of a circular rash pattern. However, nummular eczema starts as tiny spots that turn into a rash, while ringworm spreads out with a clear center encircled by a discolored ring. These spots measure 2–10 cm across, although they may be smaller. On lighter skin tones, they appear scaly and pink or red, while the areas will look much darker or lighter on darker skin tones. Itching or burning sensations in these areas worsen at night and can be severe. Often, patches will flare up in the same spots on the body, and in serious cases, patches can leak fluid or crust over.

Granuloma Annulare: A Rare, Chronic Skin Disorder

Granuloma annulare is a rare, chronic skin disorder that is not contagious or cancerous. Although the affected skin looks like ringworm, the center of the rash remains a solid color.

In this condition, a raised round rash forms with a distinctive border of small, firm bumps. These bumps grow into a ring and mainly develop on the feet, legs, hands, or arms. The rash can appear deeper in color on darker skin, with a purplish-red edge around the outside. On lighter skin tones, the site may be yellow, red, or flesh-colored. The rash is not usually painful or itchy and will often fade without treatment. There are many types of granuloma annulare, but the most common type is localized, primarily affecting children.

Lyme Disease: A Tick-Borne Illness with a Bull’s-Eye Rash

Lyme disease is a tick-borne illness that can cause a characteristic bull’s-eye rash, known as erythema migrans. This rash typically starts as a small red spot that expands over time, forming a red circle with a clear center. The rash may be accompanied by flu-like symptoms, such as fever, chills, and body aches.

While the bull’s-eye rash is a common symptom of Lyme disease, it can sometimes resemble ringworm or other skin conditions. It’s important to seek medical attention if you suspect you may have been exposed to ticks and develop any unusual skin rashes or other symptoms.

Psoriasis: Chronic Skin Condition with Scaly Patches

Psoriasis is a chronic skin condition that causes scaly, raised patches to appear on the skin. These patches can sometimes form circular or ring-like patterns, which may be mistaken for ringworm.

Psoriasis is an autoimmune disorder, and the patches are a result of the immune system attacking healthy skin cells. The patches are often red, silver, or pink in color and covered with a thick, flaky scale. Psoriasis can occur on any part of the body, but it commonly appears on the scalp, elbows, knees, and lower back.

Seek Medical Attention for Persistent or Concerning Skin Rashes

If you have a persistent or concerning skin rash that resembles ringworm, it’s important to seek medical attention. A healthcare provider can properly diagnose the condition and recommend the appropriate treatment. Trying to self-treat a rash with antifungal creams may delay proper diagnosis and treatment, especially if the rash is not caused by a fungal infection.

By understanding the range of skin conditions that can cause ring-like or scaly rashes, you can be better prepared to seek the right medical care and get the appropriate treatment for your specific condition.