Describe the cutaneous changes in porphyria cutanea tarda.

Skin fragility with minor trauma is a common complaint, particularly over the dorsal fingers and hands. Skin lesions are usually found on the dorsal hands, fingers, and feet and sometimes on the face and upper trunk. Tense vesicles and bullae develop in these sites and heal with erosions, scarring, atrophy, milia, and pigmentary changes (Fig. 17-7). Hypertrichosis and thickened, sclerotic plaques may develop on the face and chest. Patients may not relate the skin changes to sun exposure, but on questioning, they often have a history of worsening in the summer months or following other periods of intense sun exposure.