Pityriasis Lichenoides

Espectro que inclui
  • Acute form: Pityriasis lichenoides et varioliformis acuta (PLEVA)
    • Febrile Ulceronecrotic Mucha-Habermann Disease (FUMHD) variant of PLEVA
  • Chronic form: Pityriasis lichenoides chronica (PLC)
 
Epidemiology
  • Pediatric population
  • Male predominance
 
Etiology: unknown
  • Theory: May not be an inflammatory process but rather a rapidly “abortive” lymphoproliferative state due to a stong immune response and the presence of a large population of FOXP3+ regulatory T cells (Saurat)
  • Associated with virus: VZV, HIV, parvovirus B19, mEBV
  • Medications: estrogen-progesterone, infliximab, adalimumab, statins
  • T-cell lymphoproliferative disorder?
 
Apresentação Clínica
  • Recurrent crops of spontaneously regressing erythematous to purpuric papules
  • PLEVA
    • versicles or pustules → Ulcer or erosion covered with blood → varioliform scars
    • Asymptomatic, resolves within weeks
    • FUMHD
      • Confluent necrotic skin lesions
      • Mucosal, gastrointestinal, pulmonary involvement
      • Mortality ~15%
  • PLC
    • Erythematous to red-brown and scaly papules
    • Indolent course over weeks to months, or relapsing course
      • Shorter course if diffuse distribution
      • Longest course if peripheral distribution
 
Histology
  • Interface dermatitis
  • Perivascular, periadnexal (follicular, eccrine) infiltrate
  • Lymphocytic predominance
  • Lymphoid atypia is not a standard feature
 
DDx
notion image
 
Tratamento
  • Discontinuation of suspected medication
  • Topical corticosteroids
  • Tetracyclines, macrolide antibiotics
  • Phototherapy (nbUVB)
  • Low dose weekly MTX
  • Systemic corticosteroids
  • IVIg or cyclosporin
  • TNF inhibitors