Allergic and Photoallergic Contact Dermatitis

Allergic contact dermatitis is one of the commonest allergic skin diseases caused by drugs. The main causes are attributed to the group of antibiotics, chemothera-peutics, local analgetics, antirheumatics, antimycotics, disinfectants, antihistamin-ics, as well as ingredients of the vehicles (preservatives, antioxidants, and others). Further details will be found elsewhere in this book (Chap. 13). 

Photoallergic reactions are far less common. They occur after external application or internal administration of photosensitizing drugs, combined with exposure to sunlight. In such circumstances internal administration tends to produce a more exanthematous type of eruption, while external application leads to eczematous manifestations. Transitional cases between the two forms may be encountered. 

Isatin derivatives Cyclamate, Saccharin Griseofulvin Some antirheumatics (Benoxaprafen, Carprofen) Sunscreens (p-aminobenzoic acid and derivatives benzophenones) Nalidixic acid 

Braun-Falcx) and Geisler (1962), Burckhardt (1962), Ippen (1967,1976), Rothenstein et al. (1966) 

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The arylpropionic acid derivatives often cause allergic and photoallergic contact dermatitis, and photoallergic dermatitis to ketoprofen, with cross-photosensitivity to benzophenone and tiaprofenic acid, has been reported (188). Photopatch tests to these substances were positive but patch tests were negative. 

Ophaswongse S, Maibach H. Topical nonsteroidal antiinflammatory drugs allergic and photoallergic contact dermatitis and phototoxicity. Contact Dermatitis 1993 29(2) 57-64. 

Ultraviolet-absorbent organic sun filters, particularly derivatives of PABA, dibenzoylmethane, and anthranilates, can cause both allergic and photoallergic contact dermatitis. PABA-containing formulations can stain clothing yellow and cause stinging or drying of the skin. 

Mark KA, Brancaccio RR, Soter NA, Cohen DE (1999) Allergic and photoallergic contact dermatitis to plant and pesticide allergens. Arch Dermatol 135 67-70... 

Skin A series of 14 cases of allergic and photoallergic contact dermatitis induced by etofenamate has been reported [31% According to the authors, about 20 previous cases have been described in the English language literature. 

Goday Bujan JJ, Perez Varela L, Pineyro Molina F, Diaz Roman T, Fonseca E. Allergic and photoallergic contact dermatitis from etofenamate study of 14 cases. Contact Dermatitis 2009 61(2) 118-20. 

Skin Allergic contact dermatitis [38 ] and photoallergic contact dermatitis [39 ] have been attributed to topical diclofenac. In the two cases with photoallergic contact dermatitis, there was cross-reactivity with aceclofenac. 

Urticaria and angioedema Allergic contact dermatoconjunctivitis Allergic contact dermatitis Photoallergic contact dermatitis Irritative or toxic contact dermatitis Phototoxic dermatitis Cumulative deposition... 

Although antihistamines are often used in the treatment of allergic conditions, topical use often produces skin sensitization and subsequent contact dermatitis (90,91). This effect occurs more often with the use of ethylenedia-mines and phenothiazines the latter also produce photo-allergic cutaneous reactions (92). A photoallergic contact dermatitis followed by a persistent light reaction was attributed to topical dioxopromethazine hydrochloride incorporated into a gel in a woman with periocular... 

Photoallergic responses to sunscreen products represent an area where chemical components not known to produce dermal allergic responses are activated by solar radiation to produce ACD. I45 46 It is hypothesized here that in these instances, electromagnetic radiation may activate the skin to adsorb and/or absorb species that do not so react without the incident radiation. Alternatively, the molecular species themselves are excited by the radiation to molecular states that make them more reactive to skin. Chemicals exhibiting photoallergic contact dermatitis include oxybenzone, butyl methoxy dibenzoylmethane, methoxycinnamate, and benzophenone—all molecules that are readily photoexcitedJ45 ... 

Occupational airborne allergic contact dermatitis Occupational airborne phototoxic contact dermatitis Occupational airborne photoallergic contact dermatitis Occupational airborne (immunological and/or non immunological) contact urticaria... 

Usually, but not invariably, dermatologic lesions are restricted to light-exposed areas. Changes may vary from urticaria to papular and eczematous eruptions with subsequent exfoliation and lichenification. Microscopically, it is very difficult to distinguish photoallergic reactions from nummular eczema, atop dermatitis, eczematous drug eruptions, and, especially, allergic contact dermatitis. 

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). 

The same phenothiazines or closely related compounds which are used as psychotropic drugs or as sedatives in humans are used by veterinarians and farmers as insecticides and anthelmintics for animals and birds. Table 8 lists the commercial phenothiazine insecticides and wormers used by veterinarians. Many individuals in these professions have acquired allergic contact dermatitis, photoallergic reactions, or both by spraing such phenothiazines for insect control or feeding these compounds as wormers. Such individuals must avoid using phenothiazine antihistamines because of the likelihood of producing flares of the phenothiazine dermatitis. 

Sensitisation to the topical antifungal agent, Mycanodin is difficult to quantitate. The active antifungal is 3-(2-hydroxy-5-chlorophenyl)pyrazole and this can cause contact allergic dermatitis and photoallergic reactions (Fig. 4 Burckhardt et al. 1968). The same authors showed, however, that an antihistamine co-formu-... 

Photoallergy is analogous to allergic contact dermatitis in that it is mediated by the immune system and there is no reaction with first exposure. Photoallergy is less common than phototoxicity and the concentration of drug needed to elicit photoallergy is much lower than for phototoxicity. Photoallergic dermatitis presents as an acute eczematous reaction which may be followed by lichenoid dermatitis or papules. 

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