R J G Rycroft

Reduced frequency of nickel allergy upon oral nickel contact at an early age.

From animal studies we know that oral administration of T‐dcpcndcnt antigens before sensitization effectively induces systemic immune unresponsiveness. Such ‘oral tolerance’ is persistent, dose‐dependent, antigen‐specific and presumably T suppressor cell‐mediated. Oral tolerance induction could be an effective way to prevent undesired T cell‐mediated immune functions, such as playing a role in allograft reaction, autoimmune and allergic diseases. In the present study allergic contact hypersensitivity (ACH) to nickel, currently presenting the most frequent contact allergy in man, was chosen to establish the feasibility of oral prevention of undesired T cell‐mediated immunity in man. Potentially tolerizing (oral nickel contacts via orthodontic braces) as well as sensitizing (ear piercing) events were studied retrospectively in 2176 patients attending nine European patch test clinics. Patients were interviewed by means of a confidential questionnaire. The results show that ear piercing strongly favoured development of nickel ACH. More importantly, patients having had oral contacts with nickel‐releasing appliances (dental braces) at an early age, but only if prior to ear piercing, showed a reduced frequency of nickel hypersensitivity. Frequencies of other hypersensitivities, in particular to fragrance, were not affected. These results support our view that induction of specific systemic immunologic tolerance by timely oral administration of antigens is feasible in man.

Photoallergic contact dermatitis is uncommon

Backgroundu2003Despite the enormous increase in sunscreen use, allergic contact (AC) and photoallergic (PA) reactions to ultraviolet (UV) filters are considered rare.

The frequency of fragrance allergy in patch-tested patients increases with their age

Backgroundu2003 The most likely age of sensitization to fragrance chemicals is unknown.

Dermatitis caused by physical irritants

Summary Backgroundu2003Although physical irritant contact dermatitis (PICD) is a common occupational dermatosis, it is one of the least well understood because of its multiple types, lack of diagnostic test, and the many mechanisms involved in its production.

Changing frequency of thiuram allergy in healthcare workers with hand dermatitis

Backgroundu2002Healthcare workers (clinical, allied/paramedical professions and ancillary workers) may have prolonged contact with natural rubber latex devices, particularly in the form of natural rubber latex gloves.

Analysis of para‐phenylenediamine allergic patients in relation to strength of patch test reaction

Backgroundu2002 Despite having a positive patch test reaction to para‐phenylenediamine (PPD), some patients continue to dye their hair, while others are forced to give up or abandon this practice. This difference in patient behaviour could be due to the degree of sensitization.

High frequency of simultaneous sensitivity to Disperse Orange 3 in patients with positive patch tests to para-phenylenediamine.

Cross‐sensitization between para‐phenylenediamine (PPD) and Disperse Orange 3 (DO3), among other textile dyes, has frequently been reported. We evaluated the frequency of simultaneous patch test reactions to PPD and a range of textile dyes. Retrospectively, we studied 128 patients who were patch test positive to PPD and who had also been tested to textile dyes. The dyes that most commonly also reacted were DO3 (46·1%) followed by Disperse Yellow 3 (21·9%). 80% of 55 patients who had a +u2003+ or stronger reaction to PPD also reacted to DO3. Dyes that were least likely also to react were Bismarck Brown (0%), Naphthol AS (1·06%), Disperse Yellow 9 (1·06%), Disperse Blue 3 (1·56%) and Disperse Red 11 (2·13%). We interpreted the simultaneous patch test reactions to PPD and DO3 as due either to cross‐sensitivity proper, or to metabolic conversion of textile dyes in the skin to PPD.

Comparative frequency of patch test reactions to topical antibiotics.

Summary Backgroundu2003Neomycin, clioquinol and fusidic acid are all topical antibiotics widely used in dermatological practice in the U.K., either as a single agent or in combination with topical corticosteroids. However, an adverse effect of topical antibiotics is contact sensitization.

Patch test frequency to p‐phenylenediamine: follow up over the last 6 years

While the frequency of patch test reactivity to many cosmetic allergens has decreased over the last 20 years, we have previously shown that in our clinic, the patch test reactivity to p‐phenylenediamine (PPD) has remained stubbornly high between 2.5% and 4.2% in the years when patch testing was performed with 1% PPD. Further retrospective analysis of the PPD patch test frequency over the last 6 years shows an increasing rate of PPD patch test frequency, showing an upward linear trend. This increasing trend cannot be fully explained by any increase in patch testing of Southern Asian patients or of sensitization caused by PPD exposure from ‘temporary henna tattoos’. An alternative explanation may be the increasing use of permanent hair dyes.

Contact sensitivity in women with anogenital dermatoses

Patients and Methods 201 women with anogenital dermatoses were referred to our contact dermatitis clinic over 14 years: Ill had a diagnosis of eczema, in 44 the diagnosis was unknown and in 46 the diagnosis was one of the following; psoriasis, lichen planus, vestibulitis or lichen sclerosus. 103 had a dermatosis only involving the vulva, 42 had perianal involvement only, and 56 had dermatoses involving both sites. They were tested against the European standard series, a medicament series, a corticosteroid series and their own topical medicaments. Other specific allergens were tested where relevant. Patches were removed and read at 2 days and again at 4 days.