Compound patch test

Cinnamon and balsam of Peru contain many similar allergenic compounds. Patch testing has demonstrated crossreactivity in persons with allergies to these two species (Calnan 1976 Hoskins 1984 Pfutzner et al. 2003). 

Unlike nickel, chromium metal does not produce allergic contact dermatitis. Some patients exhibit positive patch tests to divalent chromium compounds, but these compounds are considerably less potent as sensitizers than hexavalent chromium compounds. A case of chromium (chromic) sulfate-induced asthma in a plating worker, confirmed by specific challenge testing and the presence of IgE antibodies, has been reported. ... 

Samitz MH, Shrager J. 1966. Patch test reactions to hexavalent and trivalent chromium compounds. Arch Dermatol 94 304-306. 

The fourth major class of color additives is hair colorants. These compounds or their mixtures may be used only to color scalp hair and may not be used in the eye area. Use of these colorants is exempt, that is, the so-called coal-tar hair dyes may be sold with cautionary labeling, directions for preliminary (patch) testing, and restrictions against use in or near the eye. 

A 16-year-old girl with an 11-year history of frequent cold sores developed an erythematous rash and severe contact dermatitis during oral and topical aciclovir therapy (24). Patch tests showed contact sensitization to aciclovir and to the related compound ganciclovir. 

Contact allergy to topically applied aluminium compounds is rare but skin sensitization has been described (54). In one case the use of a cream for acne and hyperpigmentation was followed by dermatitis, and patch tests were positive to both aluminium sulfate and aluminium chloride. A more typical antecedent of sensitization is the injection of aluminium-adsorbed vaccines, and such patients may present with a granulomatous nodule at the site. Mixed contact sensitivity to nickel and aluminium has been reported to respond to antihistamine therapy (55). 

Contact dermatitis on the eyelids developed in a 70-year-old-woman after she had used eye-drops containing diclofenac. Patch tests were positive to both diclofenac and indometacin, suggesting possible crossreactivity between the two compounds (32). 

A hypersensitivity reaction was confirmed by patch testing in a 73-year-old woman who had taken a single (unspecified) dose of a compound formulation containing pseudoephedrine (27). This caused the memorably named baboon syndrome, a widespread symmetrical erythematous rash with papules and pustules. 

A 29-year-old man developed an infiltrative maculo-papular eruption after 1 week of itraconazole 100 mg bd for tinea corporis (44). Itraconazole was withdrawn, and the lesions disappeared within 7 days. Scratch tests, patch tests, scratch-patch tests, and drug induced lymphocyte stimulation tests for itraconazole were negative however, rechallenge with systemic itraconazole induced a maculopapular eruption on the face, hands, and the dorsa of the feet. Empty itraconazole capsules had no cutaneous effects, suggesting an allergic reaction to a metabolite of the compound. 

Table 1 lists alphabetically a large number of ingredients of cosmetics and topical drugs that can act as sensitizers some drugs are accidental contactants, for example in the pharmaceutical industry or in health personnel. For each compound, the concentration and vehicle for patch-testing, known or generally held to be adequate, are mentioned. 

The monoazoic compound Disperse Blue 124 (Figure 7) is the most frequently positive dye on patch testing with the textile series, particularly in women. It is probably the main cause of textile contact dermatitis today. It is closely related to another azo dye, Disperse Blue 106 (Figure 8), marketed since 1985, and both are frequently used together. This latter dye seems to have the stronger sensitizing potential and can provoke infiltrated lesions. Concomitant positive reactions to both Disperse Blue 106 and 124 are expected because of their structural similarity, and are very consistent. 

Note 4 Manual patch clamp assay is a gold standard for functional analysis of ion channels and their interactions with the drugs. Major limitation of this assay includes low through put, need of high amount of compound for testing, and requirement of highly skilled technician. The assay can be used in the late phase of drug discovery for lead optimization. 

Patch testing in some human case studies show some cross-reactivity between various dithiocarbamate compounds and other chemically-similar compounds. Burry et al. (1976) reported cross reactions between Mankobunt (active ingredient mancozeb) and Zineb 65 (active ingredient polymeric zinc ethylene... 

Studies on the effects of OPs/CMs have been performed with various preparations, including brain slices, cultured neurons, acutely isolated neurons, iieuroreceptors expressed in a host cell, and neuronal cell lines. The electrophysiologi-cal techniques utilized are extracellular recording, intracellular recording, and patch clamp. Similar to the studies of neuromuscular functions, various compounds were tested. Thus, it i.s extremely difficult to obtain a unified picture regarding the mechani,sm of action of OPs/CMs on. synaptic transmission. 

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