Photocontact dermatitis to hydrocortisone

Area of Science:

• Dermatology
• Photobiology
• Allergology

Background:

• Delayed positive patch tests can indicate allergic contact dermatitis.
• Hydrocortisone is a common topical corticosteroid with potential for hypersensitivity reactions.
• Photoallergic reactions are immune responses triggered by a substance and subsequent UV radiation exposure.

Observation:

• A patient exhibited a delayed positive patch test reaction to hydrocortisone.
• The reaction was specifically linked to exposure within the UV-A light spectrum.
• Concurrently, the patient presented with polymorphous light eruption, a UV-B-mediated condition.

Findings:

• The delayed hydrocortisone patch test reaction was confirmed as photoallergy.
• The action spectrum for this photoallergic reaction was determined to be UV-A.
• The patient's distinct UV-B-induced polymorphous light eruption was also noted.

Implications:

• Highlights the importance of considering photoallergy in delayed patch test reactions to topical steroids.
• Delineates UV-A as the causative wavelength for hydrocortisone photoallergy in this case.
• Underscores the possibility of co-existing photosensitive conditions with different triggers (UV-A vs. UV-B).