Photosensitivity
An abnormal cutaneous reaction to ultraviolet or visible light, either from endogenous conditions or exogenous agents such as drugs or chemicals.
Full Definition
Photosensitivity in dermatology describes an exaggerated or aberrant skin response to light exposure, producing erythema, urticaria, blistering, or lichenification beyond what normal sun exposure would cause. It is classified into photoallergy (immune-mediated) and phototoxicity (dose-dependent, non-immune), with further subtypes including drug-induced and idiopathic photodermatoses such as polymorphic light eruption. Editors should write it as one word ('photosensitivity'), not hyphenated or as two words, and distinguish it from photoageing, which is a chronic cumulative effect rather than an acute reaction. Accurate use is critical in drug safety documentation, dermatology trial reports, and patient information leaflets.
Usage
Usage note: Write as a single unhyphenated word; do not confuse the umbrella term 'photosensitivity' with the specific subtypes 'photoallergy' or 'phototoxicity' in regulatory documents.
In Context
- "The adverse-event section of the trial report required 'photosensitivity' to be listed as a side effect for patients taking doxycycline." — Clinical trial report
- "Photosensitivity reactions must be distinguished from phototoxicity in dermatological adverse-event classifications." — Drug safety data sheet