Severe cutaneous photosensitivity triggered by diclofenac

A 65-year-old man presented with an acute, severe cutaneous eruption involving the right upper extremity. One day prior to presentation, he had experienced localized arm pain and self-administered oral diclofenac in combination with a topical diclofenac formulation. Within hours of topical application, the treated area developed marked erythema, which rapidly progressed to a macular eruption with blister formation. The patient denied any prior history of drug hypersensitivity or contact allergies. On physical examination, vital signs were within normal limits, and no systemic abnormalities were identified. Dermatologic evaluation revealed an extensive, poorly demarcated erythematous and scaly plaque with vesiculation. The eruption was intensely pruritic and predominantly distributed over the right arm and hand, with limited extension to selected areas of the contralateral arm (Fig. 1). No mucosal involvement was observed. The characteristic distribution of the lesions, strictly confined to areas exposed to topical diclofenac, strongly supported the diagnosis of a diclofenac-induced photosensitivity reaction. The patient was managed with discontinuation of the offending drug, strict photoprotection, systemic corticosteroid therapy, and oral antihistamines. Progressive clinical improvement was observed, with complete resolution of the lesions and no significant scarring or long-term sequelae.

Figure 1.

Cutaneous photoallergic reaction related to diclofenac gel use.

Ethical consideration

Patient written informed consent was obtained.

Ethical committee

Comité de Investigación de la UDEM.

Registry number

18092024-CARD-CI.