Porphyrias are a group of photosensitivity disorders resulting from an inherited or acquired defect in the enzymes required to produce adequate amounts of haem, with the subsequent accumulation of porphyrins

Main groups

• Phototoxic skin porphyria (e.g. erythropoietic protoporphyria)
• Blistering and fragility skin porphyrias
• Acute attack porphyrias (some with no skin involvement, some also cause blistering and fragility)
• Severe congenetial porphyria (e.g. congenital erythropoietic porphyria)

Acute intermittent porphyria

Aetiology

• Most commonly presents in females around the age of 30
• Attacks can be triggered by dieting, alcohol, or medication changes

Pathophysiology

• Enzyme deficiency - porphobilinogen deaminase
• Porphyrin accumulated - porphobilinogen

Clinical features ****

• Acute abdomen
• Mood disturbance
• Neurological
• Seizures
• Unlikely to actually present with cutaneous symptoms

Investigations