A 30-year-old man presents with a two-week history of pruritic papules and vesicles with purple crusts on his arms and trunk, as well as a low-grade fever.
Diagnosis: Mucha-Habermann disease (also called pityriasis lichenoides et varioliformis acuta or PLEVA)
Lesions of Mucha-Habermann disease evolve in two very different ways, namely, as an efflorescence and at a petty pace. The former (acuta) begins as macules that quickly become reddish papules. They tend to transform rapidly into papulovesicles, which become necrotic and ulcerate to form eschars that heal with scars. Sometimes the process is so fulminant that hemorrhagic vesicles, and even hemorrhagic bullae, monopolize.
The expression of Mucha-Habermann disease characterized by rapid development of lesions that often culminate in vesicles is known formally as pityriasis lichenoides et varioliformis acuta. An exaggeration of the process results in fulminant Mucha-Habermann disease with widespread hemorrhagic blisters that ulcerate deeply and become covered by an eschar. Patients with this severely necrotizing form of the disease may die of it.
In contrast, slowly evolving lesions of Mucha-Habermann disease (chronica) begin as pink macules that process very slowly to red papules that become scaly. In time, they progress to scaly brown papules that, after many months, become hyperpigmented macules. The slowly evolving expression of Mucha-Habermann disease is known as pityriasis lichenoides chronica.
Integration: Unifying Concept
Clinically and histopathologically, Mucha-Habermann disease is a single distinctive pathologic process. It is not unique in being associated with lesions that may be accelerated to become blisters or decelerated to remain scaly papules. The same is true of lichen planus, which may become vesicular (bullous lichen planus) or be scaly papules, of psoriasis, which may become pustular (pustular psoriasis) or be scaly papules or plaques, and of lupus erythematosus (lupus dermatitis), which may be bullous (bullous lupus erythematosus) or simply scaly papules and plaques. Papules of pityriasis lichenoides acuta are characterized histopathologically by a wedge-shaped, superficial and deep, perivascular infiltrate of lymphocytes, and by lymphocytes scattered along the dermoepidermal junction in association with vacuolar alteration. Individual necrotic keratinocytes are present throughout an epidermis that displays ballooning and spongiosis.
Oral erythromycin, tetracycline, as well as phototherapy (NB-UVB), are indicated for the acute form, and methotrexate for fulminant form. Other treatments that have been reported to be effective include, but are not limited to: topical tacrolimus, dapsone, infliximab and IVIG.
For more information, contact Charles E. Crutchfield III, MD, at Crutchfield Dermatology or visit CrutchfieldDermatology.com.