Hyperpigmentation in Addison's disease
Why does primary adrenal insufficiency (Addison's disease) cause skin hyperpigmentation, while adrenal insufficiency caused by pituitary failure does not?
Answer D: explanation for every choice
A
Aldosterone does not regulate pigmentation.
B
Cortisol is low in adrenal insufficiency.
C
In pituitary failure, ACTH is low, which is why pigmentation doesn't increase.
D
Correct. Without cortisol's negative feedback, the pituitary makes more POMC, which is cleaved into ACTH and α-MSH.
TakeawayPrimary adrenal insufficiency: high ACTH and MSH → hyperpigmentation.
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Reviewed 2026-11-05 by a medical student. Spot an error? Report it with question ID bb179.