A former from the sub-Himalayan region presents with multiple leg ulcers. The most likely causative agent is:
Ans. c. Sporothrix schenkii (Ref: Ananthnarayan 8/e p609; Harrison 19/e p1353 18/e p1664; Journal of Neglected Tropical Diseases: vol 6.6; June 2012: 'Sporotrichosisin sub-himalayan India (PLOS NQeg Trop Dis. 2012 June 6 (6): 1673)Presence of multiple ulcers in the leg, along the lymphatic channels, in a farmer (outdoor worker) from the sub-himalayan region suggests the diagnosis of Sporotrichosis, caused by Sporothrix schenkii.SporotrichosisSporotrichosis is a subacute or chronic granulomatous mycotic infection involving primarily the skin and subcutaneous tissue with neighboring lymphatics.Subcutaneous mycosis, caused by Sporothrix schenkii (dimorphic fungi)Q, colonies are blackish (variation in pigmentation) and shiny but becomes wrinkled and fuzzy with age.Epidemiology: Sporotrichosis is worldwide in distribution, but more common among people living in temperate and subtropical regions with high humidityQ.In India, Sporotrichosis is known to be endemic in the sub-himalayan regionsQ, ranging from Himachal Pradesh in the north-west to Assam and West Bengal in the East.Sporotrichosis most commonly infects persons involved in outdoor activity such as landscaping, gardening, farming, nursery workers and green house workersQ.Sporotrichosis is the most frequently encountered subcutaneous mycosis in the sub-himalayan beltQ.Source of Infection: Acquired from thorn pricksQ of rose, sphagnum moss, etc. into subcutaneous tissue through minor trauma.Clinical features: Most cases occur in upper limbQ, usual site of infection is extremityQ (facial lesion in case of children) A papule or nodule develops at the site of inoculation after days or weeks. The papule or nodule the softens and breaks down forming an indolent ulcer. Sporotrichosis is characterized by an asymptomatic nodule, which over a period of time becomes ulcerated nodules, lesions are usually arranged In 'linear fashion' along the lymphatic drainageQ. Pulmonary Sporotrichosis, extra-cutaneous Sporotrichosis, is usually present as single chronic cavitary upper lobe lesion, portal is probably lung.Diagnosis: Culture (most reliable)Q of pus, joint fluid, sputum or skin biopsy in which septate hyphae carrying flower like cluster of small conidia is seen. In tissues, fungus is seen as 'cigar shaped yeast'Q (yeast cell without mycelia) Sometimes 'Asteroid bodies'Q can be seen which is formed due to antigen-antibody reaction.Treatment:Cutaneous Sporotrichosis: DOC is ItraconazoleQAlternative Potassium IodideQExtra-cutaneous Sporotrichosis: DOC is IV Amphotericin BQAlternative itraconazole
Trichophyton rubrum
Cladosporium species
Sporothrix schenkii
Aspergillus
Mycology