Pityriasis lichenoides et varioliformis acuta - Skin in Adult
While the etiology is not known, the histologic infiltrate is composed of monoclonal CD8+ T lymphocytes. This may help explain its association with lymphomas and cutaneous T-cell lymphoma (CTCL).
Pityriasis lichenoides chronica (PLC) is a related but more chronic form. In contrast to the crusts, vesicles, and pustules seen in PLEVA, PLC takes on a more indolent course and is characterized by crops of scaly erythematous papules that spontaneously regress over months (instead of weeks).
Variants of PLEVA include those with systemic manifestations such as fever, generalized lymphadenopathy, malaise, arthralgias, and arthritis. A severe variant, pityriasis lichenoides, ulceronecrotic, hyperacute (PLUH), is defined by more severe cutaneous and systemic findings. Large lesions with necrotic centers, ulcers, and diffuse purpuric papules can occur. Higher fevers, myalgias, arthralgias, CNS, and gastrointestinal symptoms have been described. PLUH carries a 25% mortality rate and is considered a dermatologic emergency.
PLEVA is generally viewed as a benign lymphoproliferative disorder that lasts from 1-3 years, depending on the distribution of lesions. However, there are case reports of progression to CTCL. No guidelines have been established for monitoring this possible progression.
L41.0 – Pityriasis lichenoides et varioliformis acuta
86487001 – pityriasis lichenoides et varioliformis acuta
- Lymphomatoid papulosis – Predominantly CD30+ cells in the infiltrate, in older patients, characterized by more nodular lesions, and active lesions do not spontaneously resolve as quickly as PLEVA.
- Vasculitis – Check serologies for RF, ANA, anti-ds DNA, ANCA, cryoglobulins. C3, C4 levels. Lesions are mostly purpuric and more monomorphous.
- Varicella – Prodrome of mild fever, malaise, and myalgia followed by pruritic erythematous papules. Lesions are pruritic. Recurrent eruptions are not a feature of varicella.
- Arthropod bites
- Dermatitis herpetiformis – Exquisitely pruritic. Ruled out by direct immunofluorescence on the skin biopsy.
- Pityriasis rosea – Herald patch, scaly papules/plaques. Crusts, vesicles, and bullae are not common findings.
- Lichen planus – Very pruritic; lesions are typically monomorphous and rarely crusted.
- Cutaneous T-cell lymphoma tends to present with larger patches and plaques.
- Perforating dermatoses
- Primary HIV infection
- Erythema multiforme
- Guttate psoriasis