Niacin and sun sensitivity: what to know

Niacin can widen small blood vessels near the skin surface, producing warmth, redness, tingling, or burning that is often most noticeable on the face, neck, or upper chest. Sun exposure can add a separate ultraviolet injury, causing redness, tenderness, or blistering. A reaction that follows dosing is not automatically sun sensitivity, and a rash can also represent a drug eruption or another skin condition.

Write down when symptoms appear in relation to niacin, how long they last, which areas are exposed, and whether the skin is raised, blistered, or peeling. This helps separate flushing from a sun-triggered eruption.

Limit direct sun when symptoms are active, use shade and protective clothing, and apply broad-spectrum sunscreen to exposed skin as directed on its label. Reapply after swimming or heavy sweating. Avoid tanning devices and new fragranced products while the skin is reactive. Speak with the prescriber before changing niacin, especially if it was prescribed for an ongoing health condition.

Seek urgent help for trouble breathing, facial or throat swelling, faintness, widespread blistering, skin peeling, severe pain, or sores in the mouth or eyes. Arrange prompt assessment for a spreading rash, fever, marked swelling, or sun-exposed skin that is painful and blistered. Persistent sensitivity despite avoiding sun also merits review.

Ask whether your symptoms fit flushing, sun sensitivity, or a drug eruption; whether the niacin dose or formulation should change; and which sunscreen or soothing product is suitable for your skin.