Addison Disease Oral Pigmentation — ORE Part 1 MCQ

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ModerateOral MedicineAddison Disease Oral PigmentationORE Part 1

A patient with confirmed Addison disease (primary adrenal insufficiency) has diffuse brown macules affecting the lips, buccal mucosa and gingiva. Which mechanism best explains this finding?

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Correct answer: B — Increased ACTH stimulates melanocortin receptors and melanin production

**A is correct.** In primary adrenal insufficiency, low cortisol removes negative feedback on the hypothalamic-pituitary axis, causing increased ACTH production. ACTH has melanocortin activity and increases melanin production, producing diffuse mucocutaneous hyperpigmentation. Oral sites, including the buccal mucosa, lips and gingiva, may be involved; NICE specifically identifies buccal-mucosal assessment when adrenal insufficiency is suspected. **B** reverses the physiological change: ACTH is raised, not reduced. **C** is incorrect because cortisol deficiency, rather than cortisol excess, is responsible. **D** describes a finding not caused by Addison disease. **E** is incorrect because diffuse, multifocal pigmentation in this context is a characteristic benign endocrine manifestation, although an atypical solitary or changing pigmented lesion would require separate assessment.

Reference: National Institute for Health and Care Excellence. Adrenal insufficiency: identification and management (NG243), recommendation 1.2.2, 2024. https://www.nice.org.uk/guidance/NG243/chapter/recommendations