uring spring and summer months, our Canadian intuition is to get out and enjoy the warm weather while it lasts, but a reaction to the sun can keep some Canadians indoors. Photosensitivity (or sun sensitivity) is an inflammation of the skin triggered by the combination of sunlight with certain medications or substances. This reaction causes redness (erythema) of the skin and may look and feel similar to sunburn or rash. The condition can occur even after brief exposure to sunlight in warm or cold weather. Reactions typically clear up once the medication is discontinued, but some people may continue to be sensitive to sunlight long after discontinuing use of the offending medication or lotion, while it clears from the body.

Reaction + cause
• Phototoxic reactions are most common, where the drug is activated by exposure to sunlight, commonly ultraviolet A (UVA), quickly causes skin damage, but ultraviolet B (UVB) may also contribute to this reaction.

• Photoallergic reactions occur when ultraviolet exposure changes the structure of the drug and is seen by the body’s immune system as an invader (antigen). The immune system initiates an allergic response to cause inflammation of the sun-exposed skin. This usually resembles eczema and is generally chronic.

To prevent triggering a reaction, avoid prolonged exposure to sunlight and wear protective clothing. If outdoors, for extra protection when exposure cannot