Phototherapy is contraindicated with which condition?

• A. G6PD deficiency
• B. Crigler-Najjar syndrome type I
• C. Congenital erythropoietic porphyria
• D. Hyperbilirubinemia

Answer: (C)

Phototherapy lowers bilirubin by using blue light to convert unconjugated bilirubin into water-soluble forms that can be excreted. In congenital erythropoietic porphyria, porphyrins accumulate in the skin and are highly photosensitive; exposure to light triggers photochemical reactions that cause painful skin damage, blistering, and other phototoxic effects. Because light exposure would worsen the eruption of symptoms in CEP, phototherapy is contraindicated. The other conditions listed do not carry the same risk: G6PD deficiency may raise concerns about hemolysis in some contexts, but phototherapy itself is not contraindicated; Crigler-Najjar type I involves severe unconjugated hyperbilirubinemia but phototherapy can still be used to reduce bilirubin levels; hyperbilirubinemia is the condition treated with phototherapy, not a contraindication.