hydroa vacciniforme

Etiology

• photodermatosis of unknown origin
• Ultraviolet radiation & Epstein Barr virus are 2 potential triggers

Epidemiology

• rare
• bimodal incidence in early childhood (1-7 years) & adolescence (12-16 years)

Pathology

• intraepidermal reticular degeneration & cellular necrosis
• spongiosis, focal epidermal necrosis, & intraepidermal lymphocytes
• skin biopsy:
  • immunohistochemistry
    • EBV latent membrane protein-1
    • EB nuclear antigen
  • Eptein Barr virus DNA

Clinical manifestations

• recurrent vesicles on sun-exposed skin that heal with vacciniform or varioliform scarring
• vesicles occur within minutes to hours of sun exposure
• resolution of the acute phase & progression to scarring occur over ~6-8 weeks
• chronic remitting & relapsing course
• characteristic seasonal flare (early summer)
• cases remit spontaneously by late adolescence with persistent scarring

* image:

Complications

• transformation lymphoma & secondary hemophagocytic lymphohistiocytosis
• extracutaneous involvement is infrequent
  • cartilage destruction
  • ocular involvement: photophobia & keratoconjunctivitis

Differential diagnosis

• erythropoietic protoporphyria
• polymorphic light eruptions
• bullous lupus erythematosus
• porphyrea cutanea tarda
• lymphoma
  • may present with tissue necrosis, involvement of photoprotected sites, presence of facial edema, extracutaneous involvement (liver, lung)

Management

• avoid sun exposure
• use of high SPF suncreen with UV-A blocking
• topical corticosteroids
• phototherapy
  • low-dose, narrow-band UV-B (TL-01) phototherapy, either daily or 3 times a week in the spring
  • psoralen photochemotherapy (PUVA) prophylactically in older patients may be of benefit
• antimalarials have been used

More general terms

• skin disease (dermatologic disorder, dermatopathy, dermatosis)