The skin is the largest and most easily visible organ of the body, so many people notice problems with their skin, such as rashes. Because rashes are often diagnosed visually, based on their appearance and pattern, some may get misdiagnosed. A number of different conditions can cause circular rashes in children, although perhaps most people might think of the infection known commonly as ringworm.
Tinea corporis, is a superficial infection of the skin, meaning it only affects the top layer. Although caused by a fungus, tinea corporis is typically referred to as "ringworm." The characteristic "rings" of ringworm are itchy, circular areas of the skin with a clear patch in the center. although there can be many variations in appearance.
Usually, the diagnosis is made based on just the appearance of these rings, but it can be confirmed by scraping a bit of skin from the ring around the edge and preparing it with a special solution to look under a microscope to see the branches of fungus causing the infection.
Treatment for ringworm is usually an antifungal cream applied directly to the skin.
Eczema, a non-contagious, itchy, recurring skin rash, is one of the most common and stressful of all chronic skin disorders. A particular kind of eczema, called nummular eczema or discoid eczema, also causes a circular rash, most commonly on the legs and buttocks of children. Unlike ringworm, nummular eczema does not have the central clearing. The lesions of the rash look more like coins than rings.
Herald Patch of Pityriasis Rosea
According to the American Academy of Dermatology website, the herald patch of pityriasis rosea is often mistaken for ringworm. However, no fungus will be seen under the microscope, and antifungal creams will not work. After some time, more oval patches will appear on your child's body and typically form a pattern on the back that resembles the outline of a Christmas tree.
Granuloma annulare, like ringworm, forms a ring-shaped lesion, but it usually is not itchy and feels firm to the touch. However, a doctor might still need to do a biopsy of the rash to make sure.
Target Lesion of Lyme Disease
Lyme disease is a bacterial infection spread by ticks. At the site of the tick bite, a ring-shaped or bull's eye appearance develops. The patient's history, such as a recent camping trip or tick bite, might be a clue that this rash would be an early sign of Lyme disease, but occasionally, it might be confused with granuloma annulare.
Seeing A Doctor
Any circular rash, especially in children, should probably be examined by a doctor to make an accurate diagnosis. Patients should also tell their doctor if the rash does not get better with the treatment, because the correct diagnosis may not have been made. Sometimes a referral to a dermatologist is necessary.
Is This an Emergency?
- "Atlas of Pediatric Physical Diagnosis, 5th edition;" Basil J Zitelli. and Holly W. Davis; 2007
- American Osteopathic College of Dermatology: Nummular Eczema
- American Academy of Dermatolog: Pityriasis Rosea
- American Academy of Dermatology: Granuloma Annulare
- CDC Public Health Image Library: Lyme Disease