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 pink 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 progress very slowly into redder 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.”
In short, rapidly-evolving lesions of Mucha-Habermann disease can become vesicles within days, eschars within a few weeks, and scars thereafter. Slowly evolving lesions of Mucha-Habermann disease play out their lives as scaly papules over many months and sometimes years. The disease itself is unpredictable in terms of longevity; its acute expression is sometimes finished in weeks, whereas its chronic manifestation sometimes sputters for years.