According to WebMD, a red ring or circle on the skin is a common symptom of ringworm, a fungal infection that is common in children and easily spread via skin-to-skin contact and contact with contaminated clothing, towels and combs. The primary symptom of ringworm is a ring of red blisters or scaled skin.
Medline Plus explains that ringworm can affect individuals of all ages. Symptoms can develop on the body, feet, groin area, beard and scalp. The red patches of ringworm tend to be light-colored in the center and surrounded with a darker ring of blisters. Ringworm is treated with antifungal creams and powders. If the infection is severe or recurrent, stronger medications are often prescribed.
According to the Mayo Clinic, a red circle on the skin is also a common symptom of Lyme disease, an illness transmitted by bacteria-carrying deer ticks. Deer ticks are prevalent in heavily wooded areas and spread the disease to humans when feeding. The most common indicator of Lyme disease is a red bump at the site of the bite that gradually forms a pattern consisting of a red ring surrounding clear skin. Additional symptoms include fever, chills and body aches. Later symptoms of Lyme disease include joint pain, severe fatigue and neurological problems. Recovery is possible if Lyme disease is diagnosed and treated in its early stages.