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Exposure to elemental aluminum and its salts is unavoidable. Aluminum as a metal is present in transport, construction, packaging, and electronic equipment. Aluminum salts are present in consumer products, food items and drinking water, vaccines, drugs, and antiperspirants. Aluminum in vaccines and preparations for allergen-specific immunotherapy are the major sensitization sources. The predominent clinical manifestations of aluminum allergy are pruritic subcutaneous nodules and eczematous dermatitis. Patch testing shall be performed with aluminum chloride hexahydrate (ACH) in petrolatum. The preparation with ACH 10% detects substantially more aluminum allergy than ACH 2%. A patch test with elemental aluminum, for example, an empty Finn Chamber, is only positive when there is a strong aluminum allergy. A patch test reading should be performed 1 week after the application so as not to miss 15% to 20% of aluminum allergy. Aluminum should be included in any baseline patch test series for children and investigated for a possible inclusion in baseline series for adults. Aluminum test chambers can interfere with the testing resulting in both false-negative and false-positive patch test reactions to nonaluminum contact sensitizers.
There is overwhelming evidence that many delayed cutaneous adverse drug reactions (beginning >6 hours after drug intake) are mediated by delayed-type (type IV) hypersensitivity, including maculopapular eruptions, erythroderma, symmetrical drug-related intertriginous and flexural exanthema/baboon syndrome, eczematous eruptions, fixed drug eruptions, acute generalized exanthematous pustulosis, and drug reaction with eosinophilia and systemic symptoms/drug-induced hypersensitivity syndrome. Therefore, after resolution of the reaction, patch tests should be performed as first diagnostic method to identify the culprit drug(s). This article provides tools to perform drug patch tests properly and safely, discussing clinical history, indications, procedure, drug patch test materials, sensitivity, the meaning of negative patch tests, and safety of the procedure. In addition, a literature review of eruptions and culprit drugs is provided in tabular format.
Recently, aluminum chloride hexahydrate (ACH) 10.0% petrolatum (pet) was recommended for patch testing to detect aluminum contact allergy. Aluminum lactate (AL) may be as reliable a test substance as ACH.
We aimed to investigate the frequencies of aluminum allergy when ACH and AL were used in patch testing consecutive patients.
Petrolatum preparations of ACH 10.0% and AL 12.0% were added to the baseline series in 2010–2017. Aluminum chloride hexahydrate 10.0% pet was added to the children baseline series from July 1, 2012, to December 31, 2017.
A total of 5448 patients were patch tested with the extended baseline series and 196 children with the extended children baseline series. Forty-eight of the 5448 adults (0.9%) and 10 of the 196 children (5.1%) were diagnosed with aluminum contact allergy. A significant difference was found between the aluminum allergy frequencies in children and adults patch tested with ACH in 2013–2017 (
Patch testing with ACH and AL demonstrated similar contact allergy frequencies. To detect aluminum allergy, patch testing with ACH 10.0% pet is recommended. Aluminum chloride hexahydrate 10.0% pet should be considered for inclusion in baseline series for patch testing adults and children.
Ethylhexylglycerin (EHG) is a recently recognized contact allergen.
The aims of the study were to characterize individuals with positive patch test reactions to EHG and to analyze reaction strength, clinical relevance, and allergen sources.
This study was a retrospective analysis of the patients patch tested to EHG (5% petrolatum) by the North American Contact Dermatitis Group (2013–2018).
Of 15,560 patients tested to EHG, 39 (0.25%) had positive (final interpretation of “allergic”) reactions. Most were female (71.8%) and/or older than 40 years (76.9%). There were no statistically significant differences between age, sex, or atopic history when compared with EHG-negative patients. The most common anatomic sites of dermatitis were the face (28.2%) and scattered generalized distribution (25.6%). Most EHG-positive reactions were + (35.9%) or ++ (33.3%). Current clinical relevance was high (79.5%); none, however, were related to occupation. Personal care products were the most common source of exposure to EHG (59.0%).
Ethylhexylglycerin is a rare contact allergen; the positive frequency of 0.25% is similar to other low allergenic preservatives including parabens, benzyl alcohol, and phenoxyethanol. The patch test concentration of 5.0% seems to be nonirritating. Although relatively uncommon, EHG reactions were usually clinically relevant (79.5%), often because of moisturizers/lotions/creams.
Carvone, a flavoring agent, may cause allergic contact dermatitis. This study summarizes patch test reactions to carvone in patients tested by the North American Contact Dermatitis Group, 2009 to 2018.
This was a retrospective analysis of patients positive to carvone (5% petrolatum). Demographics were compared with those of patients who were negative. Other analyses included reaction strength, clinical relevance, coreactivity with other fragrance/flavor allergens, and exposure sources.
Of 24,124 patients tested to carvone, 188 (0.78%) were positive. As compared with carvone-negative patients, carvone-positive patients were significantly more likely older than 40 years (
Ten-year prevalence of carvone sensitivity was 0.78%. Most carvone-positive patients were female, were older than 40 years, and/or had facial dermatitis. Personal care products were the most common source. Two-fifths of carvone reactions would have been missed by relying on other fragrance/flavoring allergens.
The underlying mechanisms of residual facial dermatitis on dupilumab (RFDD) in patients dupilumab therapy for atopic dermatitis are poorly understood.
We sought to determine the incidence of RFDD in patients receiving dupilumab and the rate of resolution of RFDD after expanded series patch testing (ESPT) and allergen avoidance.
This is a retrospective chart review of 80 patients with atopic dermatitis who were evaluated for RFDD after treatment with dupilumab. Expanded series patch testing findings and response to allergen avoidance were assessed in the subset of patients with RFDD who subsequently underwent ESPT while continuing to receive dupilumab.
Forty-nine patients (61.3%) experienced facial dermatitis before initiating dupilumab. Thirty-five patients (43.8%) experienced RFDD after starting dupilumab. Of the 14 patients with RFDD who received ESPT, 92.9% had 1 or more relevant positive patch test results, with 50% of such patients being mostly to completely clear of facial dermatitis after allergen avoidance. Importantly, 50.6% of the positive reactions to allergens were not included on the North American Contact Dermatitis Group Core 80.
Many patients with RFDD benefit from patch testing and subsequent allergen avoidance. Expanded series patch testing should be offered to patients who experience RFDD after beginning dupilumab therapy to ensure that such patients have eliminated any exogenous component of their dermatitis, such as concomitant allergic contact dermatitis.
Shoe contact allergy can be difficult to diagnose and manage.
The aim of the study was to characterize demographics, clinical characteristics, patch test results, and occupational data for the North American Contact Dermatitis Group patients with shoe contact allergy.
This is a retrospective study of 33,661 patients, patch tested from 2005 to 2018, with a shoe source, foot as 1 of 3 sites of dermatitis, and final primary diagnosis of allergic contact dermatitis.
Three hundred fifty-two patients met the inclusion criteria. They were more likely to be male (odds ratio = 3.36, confidence interval = 2.71–4.17) and less likely to be older than 40 years (odds ratio = 0.49, confidence interval = 0.40–0.61) compared with others with positive patch test reactions. The most common relevant North American Contact Dermatitis Group screening allergens were potassium dichromate (29.8%),
Shoe contact allergy was more common in younger and male patients. Potassium dichromate and
Differences in patterns of allergic contact dermatitis (ACD) among underrepresented minority populations are not well studied.
The aim of the study was to investigate patterns of ACD in African American and White patch-tested patients in a distinct metropolitan area over a 10-year period.
We conducted a retrospective review of 297 ACD patients patch tested from 2009 to 2019. Differences in allergen frequency, relevance, and sources of exposure were evaluated. Fisher exact test analyses were performed to examine these differences.
Among 297 patients, 215 were White and 47 were African American. The most common sensitizers differed between the 2 groups. African American patients also reacted with statistically significant greater frequency to disperse dye blue (
Our study highlights the differing patterns of sensitization seen in African American and White patients. This is likely due to differences in personal care product use or occupational allergy. Additional studies with larger sample sizes are needed to expand upon these differences.
Dental personnel are at risk of developing occupational contact dermatitis.
The aims of the study were to determine prevalence of occupational contact dermatitis in dental personnel referred for patch testing and to characterize relevant allergens and sources.
The study used a retrospective, cross-sectional analysis of the North American Contact Dermatitis Group (NACDG) data, 2001–2018.
Of 41,109 patients, 585 (1.4%) were dental personnel. Dental personnel were significantly more likely than nondental personnel to be female (75.7% vs 67.4%,
Occupational contact dermatitis is common in dental personnel referred for patch testing. Comprehensive testing beyond screening series is important in these patients.
Hair care products (HCPs) may cause both allergic contact dermatitis (ACD) and irritant contact dermatitis (ICD).
The aims of the study were to determine the prevalence of HCP-associated ICD/ACD and to characterize relevant allergens.
This study is a retrospective analysis of North American Contact Dermatitis Group (NACDG) patch test data, 2001–2016.
Of 38,775 patients tested, 3481 (9.0%) had positive patch test reactions associated with HCPs. The HCP-positive patients were significantly more likely to be female (79.9% vs 66.0%) and/or have primary sites of dermatitis on the face (32.0% vs 27.8%) or scalp (15.4% vs 2.2%) compared with the HCP-negative patients (
Of the HCP-positive patients, 18.5% had HCP reactions to allergens not on the NACDG screening series, underscoring the importance of patch testing to expanded series in patients suspected of HCP allergy.