Topical immunotherapy with contact sensitizers: a model to study the natural history of delayed hypersensitivity

Abstract

So-called 'topical immunotherapy' (TI) is a well-established treatment modality based on the use of potent contact sensitizers, such as squaric acid dibutylester (SADBE), that are not found in the general or occupational environment of man, and do not induce cross-sensitization to other substances. Thus, unlike patients with sensitivity to other more or less commonplace allergens, subjects submitted to this treatment modality might provide useful data for the study of the natural course of contact sensitivity. On the basis of these premises, we have retrospectively reviewed 40 patients who had consecutively received TI with SADBE for severe alopecia areata and viral warts in the period 1993-2001, and returned to visit after a 1-7-year period since the last therapeutic challenge with the sensitizer. The chronological profile of loss of contact sensitization of this case cohort has been evaluated and compared to that of other series available in the literature. Provided more standardized TI application procedures are established, aim-oriented studies of the outcome of this treatment modality may bring useful data to be employed in construction of predictive models of decay of contact sensitization under conditions of antigen avoidance.

Sensory TRP channels contribute differentially to skin inflammation and persistent itch

“…Contact hypersensitivity (CHS) in allergic contact dermatitis (ACD) is a cutaneous immune response elicited by hapten sensitization, which is primarily mediated by dermal dendritic cells (DC) and both CD4 + and CD8 + T cells 1 – 3 . Squaric acid dibutylester (SADBE), a small molecule hapten, is commonly used in the treatment of alopecia areata and warts but often causes CHS 4 , 5 . Consistent with clinical observations, SADBE can also effectively induce CHS in a mouse model of ACD in which pre-sensitization and subsequent challenges with SADBE produce marked epidermal hyperplasia and spontaneous scratching behaviors, recapitulating symptoms of ACD in humans 6 .…”

Allergic contact dermatitis from 2‐ethylhexyl acrylate contained in a wig‐fixing adhesive tape and its ‘incidental’ therapeutic effect on alopecia areata

“…No data allow to hypothesize that AA may represent a local eliciting factor in the onset of ACD. Instead, the development of ACD on AA patches can be induced for therapeutical aims through the application of contact sensitizers because a local inflammation is often capable of restoring hair growth (7). Such a phenomenon was also observed in our patient, for which ACD had achieved an ‘incidental’ improvement of AA.…”

Sophocarpine inhibits TRP channels to produce anti-pruritic and analgesic effects in a mouse model of inflammatory itch and pain

“…In the clinic, ACD-associated itch symptoms are often presented with repeated long-lasting episodes and are sometimes accompanied by pain sensation (20). SADBE is most commonly used for the treatment of pelade and warts but often causes ACD with severe itch after frequent applications, and hence SADBE is commonly used in ACD studies (21). Consistent with clinical observations, SADBE effectively induces ACD in mice, which display significant spontaneous scratching and wiping behavior (22).…”