In phototoxic reactions, the drug may become activated by exposure to sunlight and cause damage to the skin. The skin’s appearance resembles sunburn, and the process is generally acute (has a fast onset). Ultraviolet A (UVA) radiation is most commonly associated with phototoxicity, but ultraviolet B (UVB) and visible light may also contribute to this reaction.
Rash from a phototoxic reaction is mainly confined to the sun-exposed area of the skin. A phototoxic reaction typically clears up once the drug is discontinued and has been cleared from the body, even after re-exposure to light.
Symptoms of phototoxic reaction:
Individuals with phototoxic reactions may initially complain of a burning and stinging sensation. Then the redness typically occurs within 24 hours of the exposure to sun in the exposed areas of the body such as the forehead, nose, hands, arms, and lips. In severe cases, the sun protected areas of skin may be also be involved.
The range of skin damage may vary from mild redness to swelling to blister formation (bullae) in more severe cases. The rash from this photosensitivity reaction usually resolves with peeling and sloughing off (desquamation) of the affected skin within several days.