Noticing red, round patches on your arm can be worrying—especially when they appear in clusters or slowly expand. A common question people ask is: Are they contagious? The answer depends on the cause.
One of the most frequent reasons for circular rashes is ringworm (tinea corporis)—a fungal infection, not an actual worm. It usually appears as a red, round rash with slightly raised or scaly edges and a clearer center, often causing mild itching.
Yes, ringworm is contagious and can spread through:
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Direct skin-to-skin contact
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Sharing towels or clothing
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Contact with infected pets
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Touching contaminated surfaces
If the rash gradually grows or new patches appear nearby, a fungal infection becomes more likely.
However, not all circular rashes are infectious.
Eczema (nummular dermatitis) can cause coin-shaped, itchy patches due to skin inflammation—not infection.
Psoriasis, an autoimmune condition, may create red plaques with thicker, silvery scales.
Both are non-contagious and cannot spread through contact.
While ringworm often has a defined outer border, eczema tends to be dry or crusty, and psoriasis plaques are usually thicker and may appear on elbows, knees, or scalp.
If the rash spreads, becomes painful, or doesn’t improve with treatment, consult a doctor. A simple skin test can confirm fungal infection.
Early antifungal treatment usually clears ringworm within weeks.
