Prevalence and trend of allergen sensitization in patients with nummular (discoid) eczema referred for patch testing: North American Contact Dermatitis Group data, 2001–2016

Abstract

Background Few studies have examined the relationship between nummular (discoid) eczema (NE) and allergic contact dermatitis (ACD). Objective To examine trends, associations, and clinical relevance of ACD in patients with NE who were referred for patch testing. Methods Retrospective analysis of 38 723 patients from the North American Contact Dermatitis Group. Results Overall, 748 patients (1.9%) were diagnosed with NE; 23.9% had a concomitant diagnosis of ACD. The prevalence of NE fluctuated over time between 2001 and 2016, with no overall change in prevalence in diagnosed NE. In multivariable logistic regression models, NE increased steadily with age and was associated with male sex and Asian and other race/ethnicity, and inversely associated with a history of atopic dermatitis (AD) and hay fever. Patients with NE had lower proportions of one or more positive allergic reactions and lower odds of a positive reaction in multiple individual allergens. The most commonly relevant allergens in patients with NE were formaldehyde 2.0% aq., methylisothiazolinone, quaternium 15, fragrance mix I, and propylene glycol. Conclusion NE is a heterogeneous disorder with distinct subsets of lesional distributions and a profile of relevant allergens, especially formaldehyde and formaldehyde releasers. Nearly one in four patients with NE had ACD, supporting the role of patch testing in patients with NE.

S2k guideline diagnosis, prevention, and therapy of hand eczema

“…In a recent publication, the role of contact sensitization in nummular eczema was addressed, and based on the results application of epicutaneous patch testing was recommended for this patient group. 34 Fingertip dermatitis is an eczema limited to the fingertips. It is often caused by chronic skin irritation, but may, however, also occur in association with atopic dermatitis or allergic contact dermatitis.…”

“…While a significant number of patients have an underlying atopic skin diathesis, contact sensitizations seem to play a role in individual cases as well. In a recent publication, the role of contact sensitization in nummular eczema was addressed, and based on the results application of epicutaneous patch testing was recommended for this patient group 34 . Fingertip dermatitis is an eczema limited to the fingertips.…”

Contact allergy to and allergic contact dermatitis from formaldehyde and formaldehyde releasers: A clinical review and update

“…In addition to localized forms also widespread (nummular, patchy) dermatitis, airborne dermatitis, and even erythroderma, due to FA and FRs contact allergy, have been published (Table 2). 3 Moreover, FA is a commonly identified contact allergen in adults and children with atopic dermatitis, 39 and in subjects with hand dermatitis, 40 nummular (discoid) dermatitis, 41 and stasis dermatitis 42 . (Occupational) hand dermatitis and sensitization to FA might signify a worse prognosis 3 .…”

Patch Test Positivity to Palladium: A 5-Year Retrospective Study in Triveneto Region, Italy

“…A llergic contact hypersensitivity to metal allergens is a common medical condition that greatly impacts quality of life and work ability-20% of the population is estimated to be hypersensitive to metal allergens. The main cause of metal-induced allergic contact dermatitis is nickel (Ni), with a median prevalence of 8.6% (range, 0.1%-0.8%) in Europe [1][2][3] and 17.9% in the United States, 4 and an even higher value among the Italian female population, where it reaches 34.14%. [1][2][3] To reduce Ni sensitization, in 1994, the first European Ni directive was adopted and came into force in Italy in 2001, restricting the rate of Ni release from consumer products in prolonged contact with skin and in piercing posts.…”

“…[1][2][3] To reduce Ni sensitization, in 1994, the first European Ni directive was adopted and came into force in Italy in 2001, restricting the rate of Ni release from consumer products in prolonged contact with skin and in piercing posts. 4 In 2004, the limit of Ni release was lowered further, and since 2009, the Ni directive has been included in the registration, evaluation, authorisation and restriction of chemicals regulation. 5 Palladium (Pd) has been used to replace Ni in metal alloys used in dentistry, jewelry, and spectacles.…”