Type 2 Lepra Reaction : Erythema Nodosum Leprosum
Type 2 lepra reactions (aka. erythema nodosum leprosum) occur only in multibacillary leprosy (lepromatous leprosy and borderline lepromatous leprosy). There is antibody response to M. leprae antigens associated with immune complexes in circulation as well as their deposition in various tissues (skin, eyes, joints, lymph nodes, kidneys, liver, spleen, bone marrow, vascular endothelium, and testis). Vasculitis is a major pathological event in type 2 lepra reactions. Clinical features depend upon the severity of reaction and the organs affected and include: skin lesions (multiple small red painful nodules, sterile pustules and ulcers), iridocyclitis, orchitis, renal failure, and systemic manifestations (painful red swollen joints, lymphadenopathy, fever, and fatigue). Diagnosis has to be confirmed with a biopsy of a recent skin nodule which would show a heavy infiltrate of neutrophils superimposed on histiocytes containing numerous lepra bacilli. The treatment usually consists of analgesics and corticosteroids. Patients not responding to this therapy may require high dose clofazimine or thalidomide. Clinical History: The photograph shows multiple inflamed nodules and plaques over abdomen, back, neck, and upper limbs of a 52 y/o male. Biopsy of a nodule showed histiocytic infiltrate of lepromatous leprosy superimposed with acute inflammatory infiltrate. Numerous acid-fast bacilli were seen with modified Ziehl-Neelsen stain. Case courtesy of: Dr. Sanjay D. Deshmukh (Professor of Pathology) & Dr. Vishal A. Indurkar (Associate Professor of Dermatology), Dr. Vithalrao Vikhe Patil Medical College and Hospitals, Ahmednagar, India.