Tinea corporis is a fungal infection of the body, similar to other forms of tinea. Specifically, it is a type of dermatophytosis (or ringworm) that appears on the arms and legs, especially on glabrous skin; however, it may occur on any superficial part of the body.
Fungal infection, also known as mycosis, is a disease caused by fungi. Different types are traditionally divided according to the part of the body affected: superficial, subcutaneous, and systemic. Superficial fungal infections include common tinea of the skin, such as tinea of the body, groin, hands, feet and beard, and yeast infections such as pityriasis versicolor. Subcutaneous types include eumycetoma and chromoblastomycosis, which generally affect tissues in and beneath the skin. Systemic fungal infections are more serious and include cryptococcosis, histoplasmosis, pneumocystis pneumonia, aspergillosis and mucormycosis. Signs and symptoms range widely. There is usually a rash with superficial infection. Fungal infection within the skin or under the skin may present with a lump and skin changes. Pneumonia-like symptoms or meningitis may occur with a deeper or systemic infection.
Fungi are everywhere, but only some cause disease. Fungal infection occurs after spores are either breathed in, come into contact with skin or enter the body through the skin such as via a cut, wound or injection. It is more likely to occur in people with a weak immune system. This includes people with illnesses such as HIV/AIDS, and people taking medicines such as steroids or cancer treatments. Fungi that cause infections in people include yeasts, molds and fungi that are able to exist as both a mold and yeast. The yeast Candida albicans can live in people without producing symptoms, and is able to cause both superficial mild candidiasis in healthy people, such as oral thrush or vaginal yeast infection, and severe systemic candidiasis in those who cannot fight infection themselves.
Epidermophyton is a genus of fungus causing superficial and cutaneous mycoses, including E. floccosum, and causes tinea corporis (ringworm), tinea cruris (jock itch), tinea pedis (athlete's foot), and tinea unguium (fungal infection of the nail bed).
Microsporum is a genus of fungi that causes tinea capitis, tinea corporis, ringworm, and other dermatophytoses (fungal infections of the skin). Microsporum forms both macroconidia (large asexual reproductive structures) and microconidia (smaller asexual reproductive structures) on short conidiophores. Macroconidia are hyaline, multiseptate, variable in form, fusiform, spindle-shaped to obovate, 7–20 by 30–160 um in size, with thin or thick echinulate to verrucose cell walls. Their shape, size and cell wall features are important characteristics for species identification. Microconidia are hyaline, single-celled, pyriform to clavate, smooth-walled, 2.5–3.5 by 4–7 um in size and are not diagnostic for any one species.
The separation of this genus from Trichophyton is essentially based on the roughness of the macroconidial cell wall, although in practice this may sometimes be difficult to observe. Seventeen species of Microsporum have been described; however, only the more common species are included in these descriptions.