Erythema dyschromicum perstans

  • Most common in Latin Americans with skin types III and IV
  • 1st – 3rd decade

  • Thought to be due to environmental pollutants (contact, inhaled or ingested) in predisposed patients
  • Associations (by case reports):   
    • Ammonium nitrate
    • Benzodiazepines
    • Penicillin
    • Pesticides/toxins
    • Whipworm infestation
    • Human immunodeficiency virus
    • Oral contrast medium (barium sulfate)

  • Asymptomatic gray-blue/gray-brown oval macules and patches (0.5-2.5 cm) ± peripheral rim of erythema (rare)
  • Long axis of oval lesions can follow cleavage lines
  • Most common: neck, trunk, proximal arms (symmetrically)
  • Less common: asymmetric lesions on face and neck along lines of Blaschko
  • Spares palms, soles, scalp, mucous membranes 
  • Slowly enlarge over time and persist into adulthood for years
  • Spontaneously resolves in prepubertal patients (70% in 2-3 years)

  • Basal vacuolization ± colloid bodies
  • Mild lichenoid infiltrate 
  • Old lesions: pigment incontinence, epidermal atrophy, rete effacement
  • Immunoglobulin M, immunoglobulin G, fibrinogen, C3 staining

  • Post-inflammatory hyperpigmentation secondary to lichenoid drug eruption 
  • Pityriasis rosea
  • Small plaque parapsoriasis
  • Lichen planus
  • Generalized fixed drug eruption

Usually resistant to treatment!

  • Sun protection
  • Systemic corticosteroids
  • Topical corticosteroids
  • Topical retinoids
  • Topical vitamin C
  • Chemical peels
  • Oral antibiotics
  • Vitamin A
  • Dapsone 
  • Antimalarials
  • Griseofulvin