Dermatitis®

Acquired allergic contact dermatitis (ACD) causes significant morbidity. Certain occupations predispose workers to ACD, especially those that may damage the skin barrier. Allergic contact dermatitis has significant socioeconomic effects. Allergic contact dermatitis is difficult to treat, particularly if exposure is unavoidable.

The objective of this study was to establish the efficacy of intradermal steroid injections in inducing specific antigen hyposensitization when administered weekly into shifted patch-test sites.

Prospective, open-label trial included 10 patients with ACD. Each week for up to 8 weeks, patients were patch-tested to their known allergen, and the patch-test site was injected with triamcinolone. Primary outcomes were clinical score, reaction size, erythema, and thermal characteristics. Statistical analysis included regression, correlation, repeated measures, and analysis of variance with contrast variables.

Overall results suggest significant decreases in patch-testing reactions as evidenced by improved clinical scores, reaction sizes, and reduced heat production. In 3 patients, the patch test became negative. This desensitized state persisted for 2 months in 1 patient and for 4 months in the other 2 patients.

Repetitive treatments of weekly, shifted, positive patch test sites with intradermal steroid injections show a tendency toward allergen-specific hyposensitivity and in some cases to nonreactivity at repeat patch testing. This finding may influence future management of ACD.

Etiopathogenesis of nummular eczema is obscure; many causative factors have been proposed. Only a few studies investigated the relevance of contact allergy.

This retrospective study aimed to investigate the role of contact allergy in the underlying mechanism of nummular eczema.

From the 29,323 consecutive patients, we patch-tested for eczematous dermatitis of various type, 1022 (3.5%) with nummular eczema were enrolled. Data were collected for each patient, including age, sex, occupation, symptoms onset and duration, onset and spread sites, and clinical evidence or history of atopy. Histological analyses of acute phase lesions were carried out in some patients.

Peak incidence of age at disease onset was found in the third decade of life. Predominant sites of lesions were upper (75.8%) and lower (64.5%) limbs, followed by trunk, dorsum of the hands, and face and neck. Three hundred thirty-two (32.5%) of 1022 patients showed positive reactions to 1 or more allergens. Highest sensitization rates were found with nickel sulfate (10.2%), potassium dichromate (7.3%), and cobalt chloride (6.1%). Histopathology showed less pronounced spongiosis in atopic subjects and the elderly.

Because this study demonstrates that contact allergy is common with nummular eczema, patch testing is strongly advisable in every patient with persistent nummular dermatitis.

Sorbitan sesquioleate (SSO), an emulsifier in many corticosteroids, was previously found positive in 8.9% of 112 dermatitis patients.

The objective of this study was to present data on 24 of 591 dermatitis patients with reactions to SSO and/or sorbitan monooleate (SMO) on patch testing.

A retrospective chart review was conducted on 591 consecutive dermatitis patients patch tested from November 2008 to May 2010. In addition to being tested to a modified North American Contact Dermatitis Group standard series, all patients were tested to a cosmetic series.

Of the 591 patients tested, 24 reacted to SSO and/or SMO (4.1%), 19 (3.2%) reacted to SSO alone, 1 (0.17%) to SMO alone, and 4 (0.68%) reacted to both. Of the 24 sorbitan-allergic patients, 2 (8.3%) reacted to any of 4 corticosteroid screening chemicals tested.

In this follow-up study, 4.1% of 591 dermatitis patients reacted to SSO and/or SMO. Given the presence of SSO in many popular topical corticosteroid formulations, clinicians should consider allergy to sorbitans when patients do not improve with topical corticosteroid therapy.

Benzalkonium chloride (BAK) and benzethonium chloride (BEC) are well-characterized skin irritants and rare sensitizers, but optimal testing for allergic contact dermatitis (ACD) is not established.

Sensitization prevalence was sought, and several patch testing concentrations and vehicles were compared.

One hundred forty-two patients tested to the standard screening series for evaluation of dermatitis consented to additional tests including BAK 0.15% aqueous (aq), BAK 0.15% petrolatum (pet), BEC 0.15% aq, and BEC 0.5% aq. Follow-up to assess clinical relevancy included early and late patch test reads, 1-month clinical follow-up, and long-term phone calls. Patients were categorized as definite, possible, or unlikely to have ACD to BAK and/or BEC.

Atopy was not associated with patch test reactions (P = 0.154). Seventy-five percent (6/8) of the patients with possible ACD to BAK had coreactions with BEC. Testing to both BAK 0.15% pet and 0.15% aq would have identified 91% of those with possible ACD to BAK, twice as many than if only BAK 0.1% aq from the standard series was used.

Sensitization to BAK and BEC, although rare, does occur. Weak and morphologically irritant reactions at day 7 reading can be relevant. We recommend testing to BAK 0.15% aq and 0.15% pet to increase sensitivity and having patients undergo long-term follow-up.