Managing Contact Dermatitis without Patch Testing.

Allergic contact dermatitis (ACD) is a common skin condition caused by contact with an exogenous agent that elicits an inflammatory response. Patch testing (PT) is considered the gold standard for diagnosing ACD. Unfortunately, PT may not be available to some patients due to insurance and financial limitations, contributing to health care disparity, and leaving patients with undiagnosed, incompletely managed dermatitis that can have further detrimental health and occupational effects. For other patients, PT is precluded by lack of availability of specialist/expert care, comorbid medications, or diffuse disease. This article will present a patient with ACD and will work through the differential diagnosis and share strategies for empiric avoidance of suspected/common triggers. The epidemiology of ACD with respect to race and ethnicity, considerations for affordability of hypoallergenic products, access to testing, and need for future research are addressed in this article.

Prevalence of allergic contact dermatitis in children with and without atopic dermatitis: A multicenter retrospective case-control study.

BACKGROUND: As both allergic contact dermatitis and atopic dermatitis (AD) have similar clinical presentations and are characterized by spongiotic dermatitis on skin biopsy, many children with AD are not referred for patch testing and allergic contact dermatitis is underdiagnosed. OBJECTIVE: To provide updated prevalence data of common contact allergens in children with and without AD. METHODS: This is a retrospective case-control study using the Pediatric Allergic Contact Dermatitis Registry from 2018 to 2022. RESULTS: A total of 912 children were included (615 with AD and 297 without AD). Children with AD were more likely to have a longer history of dermatitis (4.1 vs 1.6 years, P < .0001), have seen more providers (2.3 vs 2.1, P = .003), have greater than 1 positive patch test (PPT) result (P = .005), have a greater number of PPT results overall (2.3 vs 1.9, P = .012), and have a more generalized distribution of dermatitis (P = .001). PPT to bacitracin (P = .030), carba mix (P = .025), and cocamidopropyl betaine (P = .0007) were significantly increased in children with AD compared to those without AD. LIMITATIONS: Technical variation between providers and potential for misclassification, selection, and recall biases. CONCLUSION: Children with AD are significantly more likely to have PPT reactions and should be referred for evaluation of allergic contact dermatitis and obtain patch testing.

Delayed allergic skin reactions to vaccines.

Background: Recent advances in vaccination against the severe acute respiratory syndrome coronavirus 2 pandemic have brought allergists and dermatologists to the forefront because both immediate and delayed hypersensitivity reactions have been reported. Objective: This literature review focused on delayed reactions to vaccines, including possible causative agents and practical information on how to diagnose, evaluate with patch testing, and manage subsequent dose administration. Methods: Currently published reviews and case reports in PubMed, along with data on vaccines from the Centers for Disease Control and Prevention web site. Relevant case reports and reviews that focused on delayed reactions to vaccines were selected. Results: Most delayed hypersensitivity reactions to vaccines include cutaneous manifestations, which vary from local persistent pruritic nodules to systemic rashes. The onset is usually within a few days but can be delayed by weeks. Multiple excipients have been identified that have been implicated in delayed vaccine reactions, including thimerosal, formaldehyde, aluminum, antibiotics, and gelatin. Treatment with antihistamines, topical corticosteroids, or systemic corticosteroids alleviates symptoms in most patients. Such reactions are generally not contraindications to future vaccination. However, for more-severe reactions, patch testing for causative agents can be used to aid in diagnosis and approach further vaccination. Conclusion: Delayed-type hypersensitivity reactions to vaccines are not uncommon. If needed, patch testing can be used to confirm agents, including antibiotics, formaldehyde, thimerosal, and aluminum. In most cases, delayed cutaneous reactions are not contraindications to further vaccine administration.

Skin testing and drug challenge outcomes in antibiotic-allergic patients with immediate-type hypersensitivity.

BACKGROUND: The evaluation of antibiotic immediate-type hypersensitivity is intricate because of nonstandardized skin testing and challenge method variability. OBJECTIVE: To determine the safety outcomes and risk factors for antibiotic challenge reactions in patients reporting a history of antibiotic immediate-type hypersensitivity. METHODS: A 5-year retrospective review of patients evaluated for immediate-type antibiotic allergy was conducted. Data analyzed included patient demographics, index reaction details, and outcomes of skin testing and challenges, classified as single-step or multistep. RESULTS: Antibiotic hypersensitivity history was identified in 211 patients: 78% to penicillins, 10% to fluoroquinolones, 7.6% to cephalosporins, and 3.8% to carbapenems. In total, 179 patients completed the challenges (median age 67 years, range 50-76 years, 56% women), and compared with nonchallenged patients, they reported nonanaphylactic (P < .001) and remote index (P = .003) reactions. Sixteen patients (8.9%) experienced challenge reactions (5 of 28 for single-step challenge, 11 of 151 for multistep challenge), and 11 of these patients had negative skin testing results before the challenge. Challenge-reactive patients were significantly younger (P = .007), more often women (P = .036), and had additional reported antibiotic allergies (P = .005). No correlation was detected between the reported index and observed challenge reaction severities (κ = -0.05, 95% confidence interval -0.34 to 0.24). Anaphylactic rates were similar during single-step and multistep challenges (3.6% vs 3.3%). CONCLUSION: In the present population, younger women with multiple reported antibiotic allergies were at greatest risk for challenge reactions. Negative skin testing results did not exclude reactions, and index severity was not predictive of challenge outcome. The multistep and full-dose methods demonstrated a comparable reaction risk for anaphylaxis.

Current strategies in treating severe contact dermatitis in pediatric patients.

Allergic contact dermatitis in children is underdiagnosed and undertreated, and its incidence is increasing. Appropriate history taking and the suspicion for allergic contact dermatitis is essential, and patch testing remains the gold standard in diagnosis. Avoidance of the offending allergen, once identified, is the first goal of treatment. Medical therapies include topical corticosteroid and topical immunomodulators. In severe cases, oral corticosteroids or immunomodulators are utilized, although prospective randomized trials for the treatment of this disease in children are lacking. A PubMed literature search was performed to identify publications on allergic contact dermatitis in the pediatric population with the keywords: dermatitis, children, allergic contact dermatitis, pediatrics, contact hypersensitivity, contact allergy, treatment, and management. This review will address the major principles behind the diagnosis and management of this disease in the pediatric population, and highlight useful strategies that may result in improved treatment of this condition.

A multi-center, retrospective review of patch testing for contact dermatitis in allergy practices.

BACKGROUND: Studies assessing patch testing (PT) in allergy practices are limited. OBJECTIVES: To determine whether PT results using a limited panel of allergens such as in the Thin-Layer Rapid-Use Epicutaneous Test (TT) as compared with an expanded panel, such as the addition of supplemental allergens (North American Contact Dermatitis [NACD] Panel, Dormer Cosmetics, hairdressing series, corticosteroid series, and personal products) will miss a significant number of positive PTs. To compare our PT results with published data from dermatology practices. METHODS: This is a 5-year multicenter retrospective chart review of PT at 3 separate allergy practices. RESULTS: Four hundred twenty-seven patients (mean age, 49.8 years) were patch tested. Eighty-two percent were female; 54% reported an atopic history. Of the standardized allergens, the 5 most common positives were nickel sulfate, fragrance mix I, p-phenylenediamine (PPD), thimerosal, and cobalt chloride. Two hundred eighteen (56.9%; 95% CI = 51.9-61.8%) patients were positive to at least 1 TT allergen. Ninety-eight (25.6%; 95% CI = 21.5-30.2%) patients were positive to both a TT and a supplemental allergen. Forty-eight (12.5%; 95% CI = 9.6-16.2%) patients were negative to a TT allergen but positive to a supplemental allergen. CONCLUSION: Positive allergens would have been missed in 12.5% of patients when evaluating with TT allergens alone, whereas 25.6% would be partially evaluated. Patch test performance characteristics for these allergy practices appear to parallel that seen for dermatology. The TT remains an adequate screening tool in an allergy practice, but a more comprehensive panel may be needed to fully evaluate contact dermatitis.

The role of contact allergy in atopic dermatitis.

Although allergic contact dermatitis (CD) was previously thought to occur less frequently in patients with atopic dermatitis (AD), more recent studies show that it is at least as common in patients with AD as in the general population, if not more so. Thus, patients with AD should be considered for patch testing (PT). Although conflicting data exist, the severity of the AD may impact the PT results. Furthermore, younger patients may yield more positive PT results. Hand eczema and compositae allergy are more common in atopic patients. Reassuringly, PT is positive for topical antiseptic and corticosteroids in only a small subset of patients. When personal products are patch tested, emollients should be included in the series.