Photoallergen

An antigen formed in the skin by photochemical (short-wave light, UV radiation) modification of a photosensitive prohapten to the hapten and via its connection with a protein in the skin. The prohapten can enter the skin exogenously or endogenously. Drugs, cosmetics and body care products are the most well-known photoallergens (see table).

• A photo patch test is performed to identify photo contact allergens in photosensitization.
• Systemic photosensitizers (see table) must be detected by systemic photoprovocation.

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2. Epstein JH (1999) Phototoxicity and photoallergy. Seminar Cutan Med Surg 18: 274-284
3. Ferguson J (2002) Photosensitivity due to drugs. Photodermatol Photoimmunol Photomed 18: 262-269
4. Fujita H et al (1965) Five cases which showed diffuse erythema and edematous papules possibly caused by saccharin, Acta Derm (Kyoto) 60: 303
5. Gordon HH (1972) Allergic reaction to saccharin. On J Obstet Gynecol 113: 1145
6. Hölzle E et al (1991) Photopatch testing: the five-year experience of the German, Austrian, and Swiss photopatch test group. J Am Acad Dermatol 25: 59-68

7. Lugović-Mihić L et al. (2017) Drug-Induced Photosensitivity - a Continuing Diagnostic Challenge. Acta Clin Croat 56:277-283.

8. Moore EN (2002) Drug-induced cutaneous photosensitivity: incidence, mechanism, prevention and management. Drug Saf 25: 345-372
9. Shudder S (2003) Solar urticaria. dermatologist 54: 952-958
10. Scheme A (2000) Adverse reactions to cosmetic ingredients. Dermatol Clin 18: 685-698
11. Schempp CM et al (2002) Plant-induced toxic and allergic dermatitis (phytodermatitis). Dermatologist 53: 93-97
12. Taub SJ (1972) Untoward reactions to saccharin. Eye Ear Nose Throat Mon 51: 405-406

Photoallergically active substances (selection)