Contact dermatitis with negative patch tests: the additive effect of allergens in combination

Abstract

We deduced on theoretical grounds that conventional patch testing would be inadequate for the detection of sensitivity to multiple allergens. Fourteen patients with positive patch tests to two unrelated allergens were studied and the response to those two allergens was measured when tested singly or in combination, using 10 different pair combinations from 15 common allergens. With serial dilutions in chloroform (14 patients) and paraffin (four patients), the response was related to the log-dose of the allergen, and change in skin-fold thickness corresponded well with clinical grading. Single allergens diluted below the threshold for a patch-test response gave a response when given in combination, the threshold for a response to one allergen being lowered by the presence of another. On the linear part of the dose-response curves the response to the mixture of allergens was additive, the combined response being the sum of the individual components. Approaching the plateau region the response to the combination was greater than to the individual allergens but less than the sum of the single responses. The same results were obtained with allergens in paraffin. We conclude that conventional single allergen patch testing by itself is inadequate for the diagnosis of contact dermatitis.

Another Look at Allergies to Fragrances: Frequencies of Sensitisation to the Fragrance Mix and Its Constituents

“…to the SCs in patch testing, different use tests [7] or, exceptionally, the lymphocyte transformation test [20] were able to detect sensitisations to SCs. Finally, haptens applied in combination may act synergistically in eliciting an allergic reaction [21]. This phenomenon was observed in the FM, too [22].…”

The Role of NK Cells in the Elicitation Phase of Oxazolone Inducing Contact Hypersensitivity

“…Alternatively, cells that infiltrate the site of hapten challenge very early during the response may also function as antigen-presenting cells. Most haptens exhibit a dose-dependent cutaneous toxicity and hapten challenge itself can condition the skin to the elicitation of CHS, as it enables neutrophil chemoattractant activity, adhesion, and activation [17,18]. Thus, the haptens by themselves are quite capable of directly inducing pro-inflammatory effects, rather than first requiring recognition of immunocompetent cells in an Ag-specific fashion.…”

Clinical update on contact allergy

“…Combined exposure to different allergens [43,44], and combined exposure to allergens along with irritants [45] significantly lowers the threshold for elicitation, and most probably also for the induction of contact allergy. This combination is very common in everyday exposures to consumer and occupational products, and perhaps the regulation of permitted concentrations for allergens should take this observation into account [46 ].…”