Porphyria Cutanea Tarda
Also written as PCT.
Porphyria: disturbed porphyrin metabolism; 5 types (congenital erythropoietic, erythrohepatic protoporphyria, acute intermittent, porphyria cutanea tarda, mixed); photosensitive subepidermal vesicles with vessel wall thickening
What our notes say
- Porphyria: disturbed porphyrin metabolism; 5 types (congenital erythropoietic, erythrohepatic protoporphyria, acute intermittent, porphyria cutanea tarda, mixed); photosensitive subepidermal vesicles with vessel wall thickening (Exam Prep: Skin Infections, Psoriasis & Pemphigus)
- Porphyria Cutanea Tarda (PCT) - Most Common Porphyria Overall: (Chemical Pathology Practice Examination)
- Phlebotomy may be used for porphyria cutanea tarda (PCT). (Endocrine & Renal Pathology — Must Know Notes)
Study material on Porphyria Cutanea Tarda
Practice questions on Porphyria Cutanea Tarda
Porphyria cutanea tarda presents with
- Acute neuropsychiatric attacks
- Photosensitive skin blistering
- Hemolytic anemia
- Abdominal pain only
Answer: B. Uroporphyrinogen decarboxylase deficiency causes porphyrins to accumulate in skin; UV light generates reactive oxygen species causing blistering on sun-exposed areas. ---
Porphyria cutanea tarda (PCT) differs from AIP in that
- It causes severe abdominal pain and psychiatric features
- It is precipitated by barbiturates and the OCP
- It presents with blistering photosensitive skin lesions on sun-exposed areas with NO neurologic features
- It is caused by accumulation of ALA and PBG
Answer: C. PCT: uroporphyrinogen decarboxylase deficiency → uroporphyrin accumulation → photosensitive blistering, skin fragility, hypertrichosis. Associated with alcohol, hepatitis C, hemochromatosis, estrogens. Urine fluoresces pink under Wood's lamp. Treatment: phlebotomy + chloroquine. ---
Porphyria cutanea tarda (PCT) differs from AIP in that it presents with
- Severe colicky abdominal pain and psychiatric features
- Motor neuropathy and autonomic dysfunction
- Elevated urinary PBG during attacks
- Blistering photosensitive skin lesions, skin fragility, and hypertrichosis on sun-exposed areas — NO neurological features
Answer: D. PCT: uroporphyrinogen decarboxylase deficiency → uroporphyrin accumulates in skin → photosensitivity, blistering, skin fragility, hypertrichosis, hyperpigmentation. Associated with: alcohol, hepatitis C, HIV, hemochromatosis (HFE mutations), estrogens. Urine fluoresces pink/red under Wood's lamp. Treatment: phlebotomy (removes iron which inhibits enzyme) + chloroquine (chelates porphyrins).
Porphyria cutanea tarda presents with ---
- Acute neuropsychiatric attacks
- Photosensitive skin blistering
- Hemolytic anemia
- Abdominal pain only
Answer: B.