Rare atypical presentations in Type 2 lepra reaction: a case series

Type 2 lepra reaction is a Th2-mediated type III hypersensitivity reaction in leprosy, with a characteristic cutaneous manifestation in the form of erythema nodosum leprosum (ENL). We describe unusual presentations of Type 2 lepra reaction in five patients.

Patient data and dermatological findings were analyzed in three men and two women diagnosed with Hansen's disease.

Findings included multiple tender, polycyclic, necrotic lesions distributed over the face in one patient, and painful, fluid-filled lesions on both arms and lower limbs in another. The third patient showed erythematous, tender nodules, bullae, and necrotic ulcers over the back and upper and lower limbs. The fourth showed erythematous tender nodules over the face, neck, back, and extremities, predominantly in sun-exposed areas. The fifth revealed multiple erythematous, severely tender nodules and urticarial plaques mimicking those of Sweet's syndrome. Diagnosis of borderline or lepromatous leprosy with atypical Type 2 reaction were made in all cases.

Type 2 lepra reactions are antigen antibody-mediated immune complex reactions that present with constitutional symptoms and ENL characterized by tender, erythematous, evanescent nodules mainly on the face, arms, and legs. Over 50% of lepromatous leprosy patients and 25% of borderline lepromatous leprosy patients experienced type 2 lepra reactions prior to the advent of multi-drug therapy. Thalidomide is the drug of choice for severe atypical lepra reactions because of its anti-tumor necrosis factor-α action. Awareness of these atypical variants and prompt diagnosis and treatment are essential to prevent mortality and morbidity in potentially treatable patients.