Topical Systemic 6-Methylcoumarin + Aminobenzoic acid and esters + Bithionol + Chlorpromazine + Diclofenac + Fluoroquinolones + Halogenated salicylanilides + Hypericin (St John's Wort) + + Musk ambrette + Piroxicam + Promethazine + Sulfonamides + Sulfonylureas + A very uncommon type of persistent photosensitivity is known as chronic actinic dermatitis. These patients are typically elderly men with a long history of preexisting allergic contact dermatitis or photosensitivity. They are usually exquisitely sensitive to UV-B, UV-A, and visible wavelengths. Diagnostic confirmation of phototoxicity and photoallergy can often be obtained using phototest procedures. . | Chapter 057. Photosensitivity and Other Reactions to Light Part 6 Table 57-4 Photoallergic Drugs Topical Systemic 6-Methylcoumarin Aminobenzoic acid and esters Bithionol Chlorpromazine Diclofenac Fluoroquinolones Halogenated salicylanilides Hypericin St John s Wort Musk ambrette Piroxicam Promethazine Sulfonamides Sulfonylureas A very uncommon type of persistent photosensitivity is known as chronic actinic dermatitis. These patients are typically elderly men with a long history of preexisting allergic contact dermatitis or photosensitivity. They are usually exquisitely sensitive to UV-B UV-A and visible wavelengths. Diagnostic confirmation of phototoxicity and photoallergy can often be obtained using phototest procedures. In patients with suspected phototoxicity determining the minimal erythema dose MED while the patient is exposed to a suspected agent and then repeating the MED after discontinuation of the agent may provide a clue to the causative drug or chemical. Photopatch testing can be performed to confirm the diagnosis of photoallergy. This is a simple variant of ordinary patch testing in which a series of known photoallergens is applied to the skin in duplicate and one set is irradiated with a suberythema dose of UV-A. Development of eczematous changes at sites exposed to sensitizer and light is a positive result. The characteristic abnormality in patients with persistent light reaction is a diminished threshold to erythema evoked by UV-B. Patients with chronic actinic dermatitis usually manifest a broad spectrum of UV hyperresponsiveness and require meticulous photoprotection including avoiding sun exposure high 30 SPF sunscreens and in severe cases systemic immunosuppression preferably with azathioprine 1-2 mg kg per day . The management of drug photosensitivity involves first and foremost the elimination of exposure to the chemical agents responsible for the reaction and minimization of sun exposure. The acute symptoms of phototoxicity may be ameliorated
