Pseudoporphyria is an acquired photosensitive blistering disease, with clinical and
immunohistological features similar to PCT. the pathogenesis is uncertain, but porphyrins
are normal.
Patients have PCT-like blistering, erosions, milia, and scars on sun- exposed skin, but,
unlike PCT, patients rarely have hyperpigmentation, hypertrichosis, sclerodermoid
changes, or dystrophic calcification.
Causes include:
• Chronic renal failure, haemodialysis, peritoneal dialysis (the antioxidant acetylcysteine
may be an effective treatment).
• UVA tanning beds, PUVA, excess sun exposure (generally women).
• A wide range of drugs, including:
– NSAIDs (most frequent cause): naproxen and others (generally in women).
– Antibiotics: nalidixic acid, tetracycline, ampicillin–sulbactam, cefepime,
fluoroquinolones.
– Antifungals: voriconazole.
– Diuretics: furosemide, bumetanide.
– Antiarrhythmics: amiodarone.
– Sulfones: dapsone.
– Vitamins: brewer’s yeast, pyridoxine.
– Retinoids: isotretinoin, etretinate.
– Muscle relaxants: carisoprodol.
– Anti-androgens: flutamide.