By Gary M. White, MD

The Lucio phenomenon (LP) is a severe necrotizing reaction of diffuse lepromatous leprosy characterized by livedo reticularis, ulcers and other signs of vasculitis.


Triangular or red patches or plaques develop on the extremities. The center may become purpuric, necrotic and then ulcerate. Escars commonly form. Secondary cellulitis or pyoderma is frequent.

Lucio Phenonmenon vs. Ulcerative Erythema Nodosum Leprosum

ENL usually presents with inflammatory nodules and plaques. Rarely, these may ulcerate, mimicking LP. The table below outlines certain key differentiating features.

Feature Lucio Phenomenon Erythema Nodosum Leprosum
Relation to Treatment Occurs in untreated Leprosy Occurs during the first 6 months of treatment of Leprosy
Clinical Feature Small, superficial ulcers Inflammatory papulonodules and plaques.
Ulcers Typical When ulcers do occur, they tend to be deep with scarring
Systemic symptoms Usually absent Fever, arterialgias, many others


Therapy is the same as for other type two reactions in leprosy. Prednisone therapy may be needed initially. Thalidomide (e.g. 400 mg/day reduced to 100 mg/day) is an alternative. Multidrug therapy for the leprosy should be continued even as the Lucio phenomenon is treated.


A sixty-three year old man gradually developed painless hemorrhagic blisters on limbs, earlobes and torso starting one year ago. These lesions later regressed spontaneously, leaving only atrophic scars on their previous sites. He also reported several bouts of recurring sinusitis, hoarseness and progressive worsening of the cutaneous lesions. The patient was cachectic, dehydrated, asthenic, dyspneic and afebrile. Physical examination showed an infiltrated face, with madarosis, besides ulceronecrotic geometrically shaped lesions affecting the limbs, torso and face. In some segments, these lesions would converge; leaving large denuded areas. Neurologic examination demonstrated bilaterally thickened fibular nerves, which were painless to palpation. Anais Brasileiros de Dermatologia


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