Which porphyria classically demonstrates the largest deposits? What are its cutaneous features?

Erythropoietic protoporphyria, also termed protoporphyria, has the largest eosinophilic deposits in cutaneous lesions. This autosomal dominant disorder of porphyrin metabolism is caused by a deficiency of the enzyme ferrochelatase (heme synthetase). Symptoms begin in early childhood and include photosensitivity, pruritus, burning, erythema, and edema. Chronic changes include a waxy, “cobblestone” thickening of the skin and shallow scars or pits. Increased protoporphyrin may be identified in the feces and blood, although urinary porphyrins are usually normal.

Lecha M, Puy H, Deybach JC: Erythropoietic protoporphyria, Orphanet J Rare Dis 4:19, 2009.