Sensitization to isothiazolinones in the Spanish Contact Dermatitis Registry (REIDAC): 2019-2021 epidemiological situation.

BACKGROUND: Current frequency and risk factors for sensitization to methylisothiazolinone (MI), methylchloroisothiazolinone/methylisothiazolinone (MCI/MI), benzisothiazolinone (BIT) and octylisothiazolinone (OIT) in Spain are not well known. OBJECTIVES: To study the frequency of sensitization, risk factors and simultaneous sensitization between the four isothiazolinones. MATERIALS AND METHODS: We analysed all 2019-2021 consecutive patients patch-tested with MI (0.2% aq.), MCI/MI (0.02% aq.), BIT (0.1% pet.) and OIT (0.1% pet) within the Spanish Contact Dermatitis Registry (REIDAC). RESULTS: A total of 2511 patients were analysed. Frequencies of sensitization were: any isothiazolinone 15.7%, MI 6.8%, MCI/MI 4.8%, BIT 3.5% and OIT 0.5%. MI and MCI/MI sensitization was associated with being occupationally active, hand dermatitis, detergents and age over 40. BIT sensitization was associated with leg dermatitis and age over 40. About one in nine MI-positive patients were positive to BIT, whereas one in five BIT-positive patients were positive to MI. CONCLUSIONS: Sensitization to MI, MCI/MI and BIT is still common in Spain, while sensitization to OIT is rare. Currently, sensitization to MI and MCI/MI seems to be occupationally related. Although its origin is unknown, sensitization to BIT is more frequent in patients aged over 40 years. Simultaneous sensitization between MI and BIT is uncommon.

Frequency of sensitization to the individual fragrances of fragrance mix I and II according to the factors included in the MOAHLFA index.

BACKGROUND: Fragrances constitute the second most frequent cause of allergic contact dermatitis in Spain. OBJECTIVES: To determine the rate of sensitization to the individual fragrances of fragrance mix (FM) I and FM II for each of the demographic and clinical factors included in the MOAHLFA (male, occupational dermatitis, atopic dermatitis, hand dermatitis, leg dermatitis, facial dermatitis, age) index. METHODS: We conducted a 5-year retrospective study in 23 Spanish centres. We identified the patients who had undergone patch testing with a specific fragrance series after reacting positively to fragrance markers in a baseline series. We obtained the MOAHLFA index items in this population, then calculated for each demographic and clinical factor the frequencies of sensitization to the individual fragrances of FM I and FM II. RESULTS: A specific fragrance series was patch tested in 1013 patients. The most frequent allergens in men, women, children, and retired people were Evernia prunastri (16%), geraniol (16.6%), isoeugenol (17.9%), and geraniol (22.4%), respectively. Citral (20.5%) and hydroxyisohexyl 3-cyclohexene carboxaldehyde (HICC) (14.5%) were the most common allergens in occupational eczemas and were also associated with a large proportion of hand and facial dermatitis. CONCLUSIONS: Frequency of sensitization to the individual fragrances of FM I and FM II varies with age, sex, affected body region, and history of occupational or atopic dermatitis.

Should methyldibromo glutaronitrile continue to be used in the European baseline Series? A REIDAC national cross-sectional study.

BACKGROUND: Methyldibromo glutaronitrile (MDBGN) was one of the most frequent and relevant allergens found in patch testing at the beginning of this century. In 2008, this preservative was banned from cosmetics in Europe and ever since the prevalence of contact allergy to MDBGN has progressively decreased. Despite that gradual decline, MDBGN is still patch-tested in most baseline series. This study assessed the frequency of MDBGN sensitization, epidemiological characteristics of allergic patients, and the relevance of positive patch tests in a nationwide Spanish registry (REIDAC). PATIENTS AND METHODS: We evaluated consecutively patch-tested patients in all participating centres. Using these data, we calculated the proportion of patients with positive patch tests to MDBGN from June 2018 to June 2020 and evaluated the relevance of the positive patch tests. RESULTS: One hundred and fourteen out of 5072 (2.24 %) tested patients were sensitized to MDBGN. Clinical current relevance was confirmed in only one case. CONCLUSION: Although the frequency of contact allergy to MDBGN remains high, no clinical significance was found in most of these patients (5072 tests needed to obtain one relevant positive result). The clinical usefulness of this allergen seems weak and its continued inclusion in the European baseline series is questionable.

Sensitization to fragrances in Spain: A 5-year multicentre study (2011-2015).

BACKGROUND: Fragrance chemicals constitute the second most frequent cause of contact allergy in Spain. There are no data available concerning the individual fragrances that are most frequently involved. OBJECTIVES: To describe the diagnostic contribution provided by specific fragrance series to the results obtained with baseline series fragrance markers by correlating the results of both series. MATERIALS AND METHODS: We performed a 5-year retrospective study of fragrance marker-positive patients tested with specific fragrance series in 23 Spanish centres. We collected the demographic and clinical characteristics, and compared the results of patch tests obtained from different suppliers. RESULTS: Of 19 588 patients patch tested with the Spanish baseline series, 1590 (8.1%) reacted positively to a fragrance marker. Of these, 1013 (63.7%) were patch tested with a fragrance series, and 664 patients reacted positively to at least one individual fragrance other than hydroxyisohexyl 3-cyclohexene carboxaldehyde. Geraniol was the most frequent allergen. Positive reactions to substances not included in fragrance mix (FM) I or FM II were found in 230 patients. Of the 436 FM I-positive patients and the 419 FM II-positive patients, 184 (42%) and 64 (39.1%), respectively, had no positive reactions to fragrance series. In the case of FM I, negative results were more common when individual fragrances were patch tested at low concentrations. CONCLUSIONS: We recommend patch testing all patients positive for any fragrance marker with a specific fragrance series. The correlation between the results of baseline series and fragrance series could be improved by increasing the concentrations of individual fragrances.

Candidate Allergens for Inclusion in the Spanish Standard Series Based on Data from the Spanish Contact Dermatitis Registry. / Alérgenos candidatos para ser incluidos en la serie estándar española a partir de los datos del Registro Español de Dermatitis de Contacto.

BACKGROUND: Standard patch test series must be updated using objective data on allergen sensitization. The Spanish standard series was last updated in 2016 and the European series in 2019, and the inclusion of several emerging allergens needs to be evaluated. MATERIAL AND METHODS: We conducted a prospective, observational, multicenter study of consecutive patients from the registry of the Spanish Contact Dermatitis and Skin Allergy Research Group (GEIDAC) who were patch tested in 2019 and 2020 with linalool hydroperoxide, limonene hydroperoxide, 2-hydroxyethyl-methacrylate, benzisothiazolinone, octylisothiazolinone, textile dye mix (TDM), sodium metabisulfite, propolis, bronopol, Compositae mix II, diazolidinyl urea, imidazolidinyl urea, decyl glucoside, and lauryl glucoside. RESULTS: We analyzed data for 4654 patients tested with diazolidinyl urea, imidazolidinyl urea, and bronopol, and 1890 tested with the other allergens. The values for the MOAHLFA index components were 30% for male, 18% for occupational dermatitis, 15% for atopic dermatitis, 29% for hand, 6.5% for leg, 23% for face, and 68% for age > 40 years. Sensitization rates above 1% were observed for 7 allergens: linalool hydroperoxide, 2-hydroxyethyl-methacrylate, benzisothiazolinone, limonene hydroperoxide, TDM, sodium metabisulfite, and propolis. Three allergens had a current relevance rate of over 1%: linalool hydroperoxide, 2-hydroxyethyl-methacrylat, and limonene hydroperoxide. Benzisothiazolinone and TDM had a relevance rate of between 0.9% and 1%. CONCLUSIONS: Our results indicate that 7 new allergens should be considered when extending the Spanish standard patch test series. The data from our series could be helpful for guiding the next extension of the European baseline series.

Perianal Dermatitis.

BACKGROUND: Perianal complaints are often consulted in dermatology clinics, and in many cases, a conclusive diagnosis is not easily made. OBJECTIVE: The aim of this study was to study and identify the epidemiological, clinical, and contact allergy features of patients with perianal dermatitis who attended at a contact dermatitis unit in a tertiary hospital in Spain. METHODS: Adult patients with long-lasting (>4 weeks) perianal dermatitis were recruited during the past 10 years for investigation and follow-up. Every patient underwent a diagnostic workup consisting of dermatological exploration and patch tests with the standard and specific series, as well as the patients' own products. General surgical exploration was also performed in some patients. RESULTS: One hundred twenty-four patients were included. The MOAHLFA index was as follows: 43.5, 0, 4.8, 11.3, 1.6, 8.1, and 75. The main final diagnoses were allergic contact dermatitis (32.3%), psoriasis (24.2%), irritant contact dermatitis (17.7%), and lichen simplex (neurodermatitis) (10%). Eighty-one patients (66.1%) showed 1 or more positive reactions, and in 52 patients (43%), positive reactions relevant to the present disease were found. CONCLUSIONS: Contact allergy in patients with long-lasting perianal complaints is frequent. It is mandatory for these patients to be referred to a dermatologist for an adequate evaluation and patch testing. Methylchloroisothiazolinone/methylisothiazolinone seems as the most common allergen implicated in perianal contact dermatitis.