Clinical Features:

• Delayed-type (type IV) hypersensitivity reaction that may develop secondary to a variety of topical agents or drugs
• Clinically resembles allergic contact dermatitis, but the rash is confined to sun-exposed areas, as the responsible agent becomes immunogenic following exposure to light

Histologic Features:

• Acute to subacute spongiotic dermatitis
• There is often a predominantly superficial dense perivascular lymphocytic infiltrate with endothelial swelling and mural edema.
• If the causative agent is present in sufficient quantities, there may be associated phototoxic features, including:
  • Keratinocyte necrosis
  • Architectural disarray and dysmaturation
  • Hyperpigmentation with transepidermal elimination of melanin
  • Hypergranulosis

Cases associated with this book:

Photoallergic dermatitis
Author: Artur Zembowicz M.D. Ph.D.

Conference: DermatopathologyConsultations.com Teaching Collection