chronic inflammation. Zoophilic organisms are found primarily in animals and cause marked inflammatory reactions in humans who have contact with infected cats, dogs, cattle, horses, birds, or other animals. Infection may also be transmitted via indirect contact with infected animals, such as by their hair. This is followed by a rapid termination of the infection. Geophilic species are usually recovered from the soil but occasionally infect humans and animals. They cause a marked inflammatory reaction, which limits the spread of the infection and may lead to a spontaneous cure but may also leave scars. Sexual reproduction Dermatophytes reproduce sexually by either of two modes, heterothallism or homothallism. In heterothallic species, interaction of two individuals with compatible mating types are required in order for sexual reproduction to occur. In contrast, homothallic fungi are self-fertile and can complete a sexual cycle without a partner of opposite mating type. Both types of sexual reproduction involve meiosis. Frequency of species In North America and Europe, the nine most common dermatophyte species are: Trichophyton: rubrum, tonsurans, mentagrophytes, verrucosum, and schoenlenii Microsporum: canis, audouinii, and gypseum Epidermophyton: floccosum About 76% of the dermatophyte species isolated from humans are Trichophyton rubrum. 27% are Trichophyton mentagrophytes 7% are Trichophyton verrucosum 3% are Trichophyton tonsurans Infrequently isolated (less than 1%) are Epidermophyton floccosum, Microsporum audouinii, Microsporum canis, Microsporum equinum, Microsporum nanum, Microsporum versicolor, Trichophyton equinum, Trichophyton kanei, Trichophyton raubitschekii, and Trichophyton violaceum. The mixture of species is quite different in domesticated animals and pets (see ringworm for details). Epidemiology Since dermatophytes are found worldwide, infections by these fungi are extremely common. Infections occur more in males than in females, as the predominantly female hormone, progesterone, inhibits the growth of dermatophyte fungi. Medications General medications for dermatophyte infections include topical ointments. Topical medications like clotrimazole, butenafine, miconazole, and terbinafine. Systemic medications (oral) like fluconazole, griseofulvin, terbinafine, and itraconazole. For extensive skin lesions, itraconazole and terbinafine can speed up healing. Terbinafine is preferred over itraconazole due to fewer drug interactions. Treatment Tinea corpora (body), tinea manus (hands), tinea cruris (groin), tinea pedis (foot) and tinea facie (face) can be treated topically. Tinea unguum (nails) usually will require oral treatment with terbinafine, itraconizole, or griseofulvin. Griseofulvin is usually not as effective as terbinafine or itraconizole. A lacquer (Penlac) can be used daily, but is ineffective unless combined with aggressive debridement of the affected nail. Tinea capitis (scalp) must be treated orally, as