Methylisothiazolinone: a case of perianal dermatitis caused by wet wipes and review of an emerging pediatric allergen

Evolution of methylisothiazolinone sensitization: a Belgian multicentric study from 2014 to 2019

BACKGROUND

In the 2010s an epidemic of allergic contact dermatitis to methylisothiazolinone occurred in Europe. European authorities banned the use of methylisothiazolinone in leave-on cosmetics in 2017 and limited its use in rinse-off products in 2018.

OBJECTIVES

To investigate the sensitization rate to methylisothiazolinone in Belgium between January 2014 and December 2019, and to assess co-sensitizations to octylisothiazolinone and benzisothiazolinone in methylisothiazolinone -sensitized patients.

METHODS

A retrospective study of patch test results with methylisothiazolinone, octylisothiazolinone and benzisothiazolinone observed in patients attending five Belgian hospitals.

RESULTS

Overall, 560 of 10.029 patients (5.58%) had a positive patch test reaction to methylisothiazolinone, and its sensitization rate decreased from 7.9% in 2014 to 3.1% in 2019. Rinse-off cosmetics, paints and detergents were the most prevalent sensitization sources in recent years. Simultaneous reactions readily occurred to octylisothiazolinone, and, surprisingly, and increasingly, also to benzisothiazolinone.

CONCLUSIONS

Contact allergy to methylisothiazolinone in Belgium has reached a pre-epidemic level, reflecting the impact of recent regulatory measures. Leave-on cosmetics, in contrast to rinse-off products, have almost disappeared as sensitization sources in Europe. Paints and detergents also remain problematic. The remarkably high number of patients (co-) sensitized to benzisothiazolinone should be a focus of future research. This article is protected by copyright. All rights reserved.

Wet Wipe Allergens: Retrospective Analysis From the North American Contact Dermatitis Group 2011-2014

BACKGROUND

Although there are several case reports of wet wipe-associated contact dermatitis, the prevalence of wipes as a source of allergic contact dermatitis in larger populations and the responsible allergens are largely unknown.

OBJECTIVE

The aim of the study was to determine the prevalence of wet wipes as a source of contact allergy and the most commonly associated allergens in a North American tertiary referral patch test population.

METHODS

Data collected from 2011 to 2014 by the North American Contact Dermatitis Group was used to conduct a retrospective cross-sectional analysis of patient demographics and patch test results associated with the triple-digit source code for "wet wipe."

RESULTS

Of the 9037 patients patch tested during the study period, 79 (0.9%) had a positive patch test reaction to an allergen identified with a wet wipe source. The most commonly associated allergens were preservatives, including the following: methylisothiazolinone (MI) (59.0%), methylchloroisothiazolinone (MCI)/MI (35.6%), bronopol (2-bromo-2-nitropropane-1,3-diol) (27.4%), and iodopropynyl butylcarbamate (12.3%). Fragrance (combined) represented 12.3%. Anal/genital dermatitis was 15 times more likely (P < 0.0001) in those with wet wipe allergy. More than 92% of patients with wipe-associated contact allergy had their contact allergens detected by the North American Contact Dermatitis Group screening series.

CONCLUSIONS

Wet wipes are an important source of contact allergy. Preservatives are the main allergens, especially isothiazolinones.

Allergenic Ingredients in Facial Wet Wipes

BACKGROUND

Allergic contact dermatitis commonly occurs on the face. Facial cleansing wipes may be an underrecognized source of allergens.

OBJECTIVE

The aim of this study was to determine the frequency of potentially allergenic ingredients in facial wet wipes.

METHODS

Ingredient lists from name brand and generic facial wipes from 4 large retailers were analyzed.

RESULTS

In the 178 facial wipes examined, a total of 485 ingredients were identified (average, 16.7 ingredients per wipe). Excluding botanicals, the top 15 potentially allergenic ingredients were glycerin (64.0%), fragrance (63.5%), phenoxyethanol (53.9%), citric acid (51.1%), disodium EDTA (44.4%), sorbic acid derivatives (39.3%), tocopherol derivatives (38.8%), polyethylene glycol derivatives (32.6%), glyceryl stearate (31.5%), sodium citrate (29.8%), glucosides (27.5%), cetearyl alcohol (25.8%), propylene glycol (25.3%), sodium benzoate (24.2%), and ceteareth-20 (23.6%)/parabens (23.6%). Of note, methylisothiazolinone (2.2%) and methylchloroisothiazolinone (1.1%) were uncommon. The top potential allergens of botanical origin included Aloe barbadensis (41.0%), chamomile extracts (27.0%), tea extracts (21.3%), Cucumis sativus (20.2%), and Hamamelis virginiana (10.7%).

CONCLUSIONS

Many potential allergens are present in facial wet wipes, including fragrances, preservatives, botanicals, glucosides, and propylene glycol.

Allergic Contact Dermatitis Due to Methylisothiazolinone in a Young Girl's Laundry Detergent

Methylisothiazolinone (MI) is an emerging and increasing cause of allergic contact dermatitis (ACD) in children. We present the case of a 7-year-old girl with an unusual dermatitis suspicious for contact allergy. Patch testing confirmed allergy to MI, found only in the patient's laundry detergent. This case highlights the importance of checking household product ingredients and the role of MI as an increasing cause of ACD in children.

Appropriate Testing of Isothiazolinones in Children

BACKGROUND/OBJECTIVE

The isothiazolinones methylchloroisothiazolinone (MCI) and methylisothiazolinone (MI) are prevalent pediatric contact sensitizers. MI allergic contact dermatitis (ACD) is underreported in the literature. The objective of the current study was to use a database of provider-reported U.S. pediatric patch test cases to evaluate the positive patch test (PPT) prevalence rates of the combined preservative test substrate MCI/MI and of MI alone.

METHODS

U.S. pediatric patch test providers in all 50 states who had joined the registry were invited to submit deidentified cases to the database. More than 1100 logged cases in the database were evaluated for PPTs to MCI/MI combination, MCI/MI and MI, and MI alone.

RESULTS

Within 1 year of data collection, 96 cases with a PPT for MCI/MI, MCI/MI and MI, and MI alone were identified; 37 of these were positive to MCI/MI, with MI alone not tested or negative, and 39 were positive to MI only, with MCI/MI and MI tested. Fifteen (41%) of the MCI/MI cases were detected using an epicutaneous patch test alone and 22 cases (59%) using comprehensive patch testing. Only one case (3%) of MI alone sensitization was detected using T.R.U.E. plus a supplemental panel of tests; the remaining 38 cases (97%) were detected using comprehensive testing. Testing with only the combined MCI/MI preservative substrate may miss 51% of MI allergies.

CONCLUSION

Appropriate testing of isothiazolinones is needed to clarify the true prevalence of sensitization to these allergens and the burden of pediatric ACD. Patch testing for MI alone in addition to MCI/MI combination is warranted in children with recalcitrant dermatitis.

[What's new in clinical dermatology?]

Dermatoses have been better characterized as hypochromic vitiligo in subjects with dark skin or the acquired racquet nails associated with hyperparathyroidism. The innate immunity has a central role in the new classification of auto inflammatory diseases, neutrophilic dermatoses, neutrophilic urticaria or pseudo-neutrophilic urticaria. Comorbidities have been studied e.g. cardiovascular co morbidities for psoriasis, IBD associated with hidradenitis suppurativa or neurological disorders associated with pemphigoid. Bullous pemphigoid could be renamed as cutaneous pemphigoid, it can be induced by drugs especially gliptins. Genetic predispositions are analyzed in auto inflammatory diseases, psoriasis (HLA), drug eruptions (HLA or cytokines). Telaprevir often induces rashes, which can be severe but other treatments against hepatitis C as interferon can also induce debilitating rashes, some eligible for drug tolerance induction. European guidelines for the definition, classification, diagnosis of chronic spontaneous urticaria have been published. Severe cutaneous adverse drug reactions may be associated with severe systemic symptoms such as organ involvement in AGEP or the occurrence of a shock in DRESS. Allover Europe, there is now an epidemic of contact allergies to methylisothiazolinone (MIT), contained in cosmetics, wet wipes but also in paints. MIT should be tested at 2.000 ppm in water, included in the standard series for patch tests. Its role has to be evoked in any case localized on the face or hand, airborne or generalized eczema. Among infectious diseases, skin manifestations due to Parvovirus have been specified, a febrile rash can be related to dengue infection or to Zika virus.

Isothiazolinones: sensitizers not to miss in children

Isothiazolinone is known to be a sensitizer and a frequent cause of contact dermatitis in adults. Cases of contact dermatitis have also recently been reported in children. Derivatives of isothiazolinone, such as methylisothiazolinone (MI) and methylchloroisothiazolinone (MCI), are commonly used in the care products of babies and children. This allergen should not be missed.

Invited commentary: recommendation for a north american pediatric patch test series

Given the increased recognition of pediatric allergic contact dermatitis and lack of patch testing consensus in children, we present a minimum basic 20-allergen North American pediatric series, for screening children ages 6-12 with suspected contact allergy.