Ringworm, known in medical terms as tinea corporis, is actually not caused by a worm, but by a fungus. Tinea corporis refers to a fungal infection of the body or face, not including the beard area on men. Ringworm occurs more commonly in warm, tropical environments, affects men and women equally, and affects all ages equally.
Ringworm - Superficial Fungus Infection
Ringworm is a dermatophyte infection. Dermatophytes are a group of related fungi that infect and survive on dead keratin, the top layer of the epidermis. The following are the most common fungi responsible for ringworm:
- Trichophyton rubrum
- Microsporum canis
- Trichophyton mentagrophytes
Ringworm - Appearance
The most common appearance of ringworm is a lesion that starts as a flat, scaly spot which then develops a raised border that advances outward in a circle. The advancing border is red, raised, and scaly while the central area is more normal appearing, usually still with fine scaling. Some ringworm infections, especially those treated with a steroid like hydrocortisone, can have vesicles or pustules in the advancing border or in the center.
Ringworm - Pictures
The following pictures give good examples of the characteristics of the rash:
Ringworm - Diagnosis
Ringworm is sometimes diagnosed clinically, based on the appearance of the classic rash. However, some ringworm infections can mimic other skin conditions such as granuloma annulare, nummular eczema, or tinea versicolor. The easiest method used to confirm the diagnosis of ringworm is a KOH test. Rarely, fungal cultures are taken to identify the exact fungus causing the infection.
Ringworm - Topical Treatment
In general ringworm responds well to topical treatment. Topical antifungals are applied to the lesion twice a day for at least 3 weeks. The lesion usually resolves within 2 weeks, but therapy should be continued for another week to insure the fungus is completely eradicated. The most commonly used antifungal creams are:
- Miconazole (Monistat)
- Clotrimazole (Mycelex)
- Ketoconazole (Nizoral)
- Terbinafine (Lamisil)
Ringworm - Oral Treatment
If there are several ringworm lesions or if the lesions are extensive, oral antifungal medications can be used. Oral medications are taken once a day for 7 days and result in a 100% clinical cure rate. The recommended oral antifungal medications are:
- Terbinafine (Lamisil) 250 mg
- Itraconazole (Sporanox) 200 mg
Preventing Ringworm
Because fungi prefer warm, moist environments, preventing ringworm involves keeping skin dry and avoiding contact with infectious material. Basic prevention measures include:
- Wash hands after handling animals, soil, and plants
- Avoid touching characteristic lesions on other people
- Wear loose-fitting clothing
- Practice good hygiene when participation in sports involves physical contact with other people
