Pityriasis lichenoides

Pityriasis lichenoides et varioliformis acuta
Pityriasis lichenoides et varioliformis acuta
	Photo of the Pityriasis lichenoides et varioliformis acuta or Mucha Habermann's Disease, showing the right leg
Specialty	Dermatology

Pityriasis lichenoides represents a distinct subset of inflammatory skin disorders that includes pityriasis lichenoides chronica, febrile ulceronecrotic Mucha-Habermann disease, and pityriasis lichenoides et varioliformis acuta (PLEVA).^[1]

PLEVA typically manifests as an acute to subacute skin eruption of several tiny red papules that grow into polymorphic lesions. It may also leave behind varicella-like scars and hyper- or hypopigmentation sequelae.^[2]

Pityriasis lichenoides chronica (PLC) has very small reddish-brown flat maculopapules with a mica-like scale that appear more gradually; it also has long remission intervals between episodes of relapse.^[2]

Febrile ulceronecrotic Mucha-Habermann disease (FUMHD) is best treated as a dermatological emergency because it is an acute, severe, widespread eruption of purpuric and ulceronecrotic plaques that can have a 25% fatality rate and accompanying systemic involvement.^[2]

Signs and symptoms

The characteristic feature of PLEVA is the rapid evolution of 2- to 3-mm-diameter

Pruritus and burning are among the symptoms. Although diffuse and widespread patterns can also occur, the trunk, extremities, and flexural areas are the most common sites for PLEVA to occur. Lesions can occur at any stage of development, making the eruption polymorphous. Subsequent crops of lesions can persist for weeks, months, or even years.^[1]

The rapid progression of necrotic

Atrophic scars and hypopigmentation are common after ulcer healing.^[1]

PLC presents with a far slower clinical course than both febrile ulceronecrotic Mucha-Habermann disease and PLEVA. Similar to PLC, the lesion begins as an

erythematous papule that turns reddish-brown and is easily detached to reveal a shiny, pinkish-brown surface. The lesion also has a centrally adherent micaceous scale. In contrast to PLEVA and febrile ulceronecrotic Mucha-Habermann disease, the papule in question regresses and flattens on its own over a few weeks. Frequently, a hyper- or hypopigmented macule is left behind.^[1]