Dermatophytoses are chronic fungal infections of keratinous structures such as the skin, hair or nails. Trichophyton, Microsporum and Epidermophyton are traditionally referred to as dermatophytes, although other fungi such as Candida can also infect keratinous structures.
Sporotrichosis is due to the saprophytic fungus Sporothrix schenckii, which is found worldwide. Infection usually follows cutaneous inoculation, at the site of which a reddish, non-tender, maculopapular lesion, referred to as ‘plaque sporotrichosis’ develops. Pulmonary involvement and disseminated disease rarely occur.
Treatment with saturated potassium iodide (10-12 rnl daily orally for adults) is curative in the cutaneous form. Amphotericin or miconazole is required for systemic infection.
Subcutaneous zygomycosis is caused by several filamentous fungi of the Basidiobolus genus. The disease usually remains confined to the subcutaneous tissues and muscle fascia. It presents as a brawny, woody infiltration involving the limbs, neck and trunk. Less commonly, the pharyngeal and orbital regions may be affected. Treatment is with saturated potassium iodide solution given orally.
Chromomycosis (chromoblastomycosis) is caused by fungi of the genus Philalophora and Cladosporium carrionii. It presents initially as a small papule, usually at the site of a previous injury. This persists for several months before ulcerating. The lesion later becomes warty and encrusted and gradually spreads. Satellite lesions may be present. Itching is frequent. The drug of choice is flucyto sine in combination with amphotericin in small doses.
Rhinosporidiosis is caused by Rhinosporidium seeberi. This organism has not been cultured. Although recognized worldwide, it is seen mainly in South India and Sri Lanka. Mucosal lesions present as polyps that are friable and vascular; the nose, nasopharynx and soft palate are most frequently involved. Haematogenous dissemination may occur. Treatment is surgical excision and cautery.