A 34-year-old male mail carrier presents with multiple brown-colored pigmented patches distributed across his face. What is the most likely diagnosis?

Correct answer: C. Melasma

• A. Addison's disease causes diffuse hyperpigmentation (bronze skin) due to elevated ACTH stimulating melanocytes, but it is accompanied by systemic symptoms (fatigue, hypotension, low BP) and the pigmentation is generalized, not patchy facial macular.
• B. Keratoacanthoma is a rapidly growing dome-shaped nodule with a central keratin-filled crater — not diffuse brown pigmentation.
• C. CORRECT. Melasma is a common hyperpigmentation disorder characterized by brown macules on sun-exposed areas of the face. It is associated with UV exposure, which a mail carrier (outdoor worker) would have significant chronic exposure to. Although melasma is more common in women, it does occur in men with significant sun exposure.
• D. Squamous cell carcinoma presents as a non-healing ulcer or indurated keratotic plaque, not as multiple diffuse brown macules. A mail carrier's sun exposure does increase SCC risk, but the description fits melasma.