What are the clinical manifestations of Penicillium marneffei infection, and how is it diagnosed?

Penicillium marneffei (PM) infection commonly presents with fever, weight loss, lymphadenopathy, hepatosplenomegaly, and characteristic skin lesions.  The lesions are papules with central necrotic umbilication distributed predominantly on the face, neck, and trunk and less often on the arms and legs.  Lesions may sometimes manifest as pustules, abscesses, nodules, or ulcers.  Mucous membrane involvement has also been described.  Cutaneous PM lesions need to be distinguished from molluscum contagiosum and lesions associated with other opportunistic infections, including cryptococcosis, blastomycosis, histoplasmosis, and TB.

Patients with PM infection often have anemia and sometimes lymphopenia, thrombocytopenia, and increased serum transaminase levels.  Diagnosis is made by identifying the fungus from a clinical specimen on smear, histopathology, or culture.  The organism may be isolated from skin, blood, lymph nodes, bone marrow, liver, or sputum. A rapid presumptive diagnosis can be made by Wright staining of a scraping from a typical skin lesion or of a bone marrow aspirate.  Definitive diagnosis is made by growth of the organism in culture.