Antihistamines photosensitivity with

Ros A, Juhlin L, Michaelsson G (1976) A follow up study of patients with recurrent urticaria and hypersensitivity to aspirin benzoates and azo dye. Br J Dermatol 95 19-24 Schreiber MM, Naylor LZ (1962) Antihistamine photosensitivity. Arch Dermatol 86 58-62 Sidi E, Hincky M, Gervais M (1955) Allergic sensitization and photosensitization to phener-gan cream. J Invest Dermatol 24 345-352... 

Photosensitivity reactions typically resolve with drug discontinuation. Some patients benefit from topical corticosteroids and oral antihistamines, but these are relatively ineffective. Systemic corticosteroids (e.g., oral prednisone 1 mg/kg/day tapered over 3 weeks) is more effective for these patients. 

Drug-induced photosensitivity reactions are divided into phototoxicity (a nonimmunologic reaction) and photoallergic reactions (an immunologic reaction). The latter form is far less common. Medications associated with photosensitivity reactions include fluoroquinolones, nonsteroidal antiinflammatory drugs, phenothiazines, antihistamines, estrogens, progestins, sulfonamides, sulfonylureas, thiazide diuretics, and tricyclic antidepressants. 

Patients with photosensitivity reactions should be treated much the same as burn victims would be management of the bum is of primary importance. Some patients benefit from topical corticosteroids and oral antihistamines, but these are relatively ineffective. Systemic corticosteroids, typically oral prednisone at 1 mg/kg per day tapered over 3 weeks, is more effective for these patients. Pharmacists and other health care professionals should encourage the proper use of sunscreen, and recommend a protective product that protects against ultraviolet A and B rays. ... 

On rare occasions the systemic administration of an antihistamine can induce allergic hypersensitivity with production of urticaria, morbilliform and scarlatini-form eruptions, erythema multiforme, photosensitivity, and anaphylactic shock. In asthmatic patients, the antihistamine may lead to bronchial obstruction with anaphylactic reactions. 

The phenothiazine drugs listed in Table 7 are all capable of cross-reacting with the phenothiazine antihistamines, and all of these compounds are potential photosensitizers (Lewis and Sawicky 1955). Often a photoallergic reaction occurs in combination with the allergic eczematous contact dermatitis. The systemic administration of the phenothiazine drugs shown in Table 7 may produce an eczematous contact dermatitis medicamentosa in individuals sensitized by such topical exposure. Cross-reactions readily take place between these phenothiazines and the related antihistamines (Mitchell and Ongley 1972). 

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