Mycetoma

Mycetoma is a chronic subcutaneous infection caused by actinomycetales(60%) or fungi(40%). This infection results in a granulomatous inflammatory response in the deep dermis and subcutaneous tissue, which can extend to the underlying bone. Mycetoma is characterized by the formation of grains containing aggregates of the causative organisms that may be discharged onto the skin surface through multi

ple sinuses. Mycetoma was first described in the mid 1800s and initially named Madura foot, after the region of Madura in India where the disease was first identified.

Mycetoma caused by microaerophilic actinomycetales(Actinomadura,N​ocardia and Streptomyces spp.) is termed actinomycetoma, and mycetoma caused by true fungi(Madurella mycetomatis M.grisea,Leptrosphaera) is called eumycetoma.



Pathophysiology

The body parts affected most commonly in persons with mycetoma include the foot or lower leg, with infection of the dorsal aspect of the forefoot being typical. The hand is the next most common location; however, mycetoma lesions can occur anywhere on the body. Lesions on the chest and back are frequently caused by Nocardia species, whereas lesions on the head and neck are usually caused by Streptomyces somaliensis.

The causative organism enters through sites of local trauma (eg, cut on the hand, foot splinter, local trauma related to carrying soil-contaminated material). A neutrophilic response initially occurs, which may be followed by a granulomatous reaction. Spread occurs through skin facial planes and can involve the bone. Hematogenous or lymphatic spread is uncommon.

INVESTIGATIONS

Diagnosis is confirmed by demonstration of fungal grains in pus
Black grains r due to eumycetoma.
Red and yellow grains r due to actinomycetoma.
Histopathological examination of tissue.

TREATMENT
Eumycetoma treated with surgery + antifunal therapy(itroconazole and ketoconozole).
Actinomycetoma treated with cotrimoxazole.
Nocardia with dapsone+cotrimoxazole.