Dermatophytosis, also known as ringworm, is a fungal infection of the skin.[2] Typically it results in a red, itchy, scaly, circular rash.[1] Hair loss may occur in the area affected.[1] Symptoms begin four to fourteen days after exposure.[1] Multiple areas can be affected at a given time.[4]

About 40 types of fungi can cause ringworm.[2] They are typically of the Trichophyton, Microsporum, or Epidermophyton type.[2] Risk factors include using public showers, contact sports such as wrestling, excessive sweating, contact with animals, obesity, and poor immune function.[3][4] Ringworm can spread from other animals or between people.[3] Diagnosis is often based on the appearance and symptoms.[5] It may be confirmed by either culturing or looking at a skin scraping under a microscope.[5]

Prevention is by keeping the skin dry, not walking barefoot in public, and not sharing personal items.[3] Treatment is typically with antifungal creams such as clotrimazole or miconazole.[7] If the scalp is involved, antifungals by mouth such as fluconazole may be needed.[7]

Globally, up to 20% of the population may be infected by ringworm at any given time.[8] Infections of the groin are more common in males, while infections of the scalp and body occur equally in both sexes.[4] Infections of the scalp are most common in children while infections of the groin are most common in the elderly.[4] Descriptions of ringworm date back to ancient history.[9]