There are a number of bullous diseases other than pemphigus and bullous pemphigoid that are important to recognize. Porphyria cutanea tarda is a disease that has no extracutaneous manifestations (Figures 194-1, 194-2, 194-3). Dystrophic epidermolysis bullosa belongs to a family of inherited diseases where blister formation can be caused by even minor skin trauma due to mechanical fragility. PLEVA (pityriasis lichenoides et varioliformis acuta) is a minor cutaneous lymphoid dyscrasia that can appear suddenly and persist for weeks to months. Dermatitis herpetiformis is a recurrent eruption that is usually associated with gluten-induced enteropathy.
Porphyria cutanea tarda in a middle-aged woman. (Reproduced with permission from Lewis Rose, MD.)
Porphyria cutanea tarda in a man with hepatitis C and alcohol abuse. (Reproduced with permission from Richard P. Usatine, MD.)
Hypertrichosis of the cheeks and temples secondary to porphyria cutanea tarda associated with his hepatitis C. This is sometimes referred to as the werewolf syndrome. (Reproduced with permission from Richard P. Usatine, MD.)
A middle-aged woman presented with tense blisters on the dorsum of her hand (Figure 194-1). One bulla was intact, and the others had ruptured, showing erosions. Work-up showed elevated porphyrins in the urine (which fluoresced orange-red under a Wood lamp) and the patient was diagnosed with porphyria cutanea tarda.
Porphyria cutanea tarda (PCT) is the most common type of porphyria disorder.1
PCT occurs mostly in middle-aged adults (typically 30 to 50 years of age) and is rare in children.
It may occur in women on oral contraceptives and in men on estrogen therapy for prostate cancer.2,3
Alcohol, pesticides, and chloroquine have been implicated as chemicals that induce PCT.1,3
PCT is equally common in both genders.
There is an increased incidence of PCT in persons with hepatitis C4-6 and HIV7 (see Figure 194-2).
ETIOLOGY AND PATHOPHYSIOLOGY
The porphyrias are a family of illnesses caused by various metabolic derangements in the metabolism of porphyrin, the chemical backbone of hemoglobin. Whereas the other porphyrias (acute intermittent porphyria and variegate porphyria) are associated with well-known systemic manifestations (abdominal pain, peripheral neuropathy, and pulmonary complications), PCT has no extracutaneous manifestations. Photosensitivity is seen (as with variegate porphyria). PCT is associated with a reduction in hepatic uroporphyrinogen decarboxylase (fifth enzyme in hemoglobin synthesis).