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Methylchloroisothiazolinone/methylisothiazolinone and moist wipe dermatitis

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Letter: Methylchloroisothiazolinone / methylisothiazolinone and moist wipe dermatitis
HR Monroe, JC Hu, MW Chiu
Dermatology Online Journal 16 (5): 14

Division of Dermatology, David Geffen School of Medicine at the University of California, Los Angeles, Los Angeles, California.


The use of moist wipes containing methylchloroisothiazolinone/methylisothiazolinone (MCI/MI), a preservative combination, has been associated with allergic contact dermatitis. Here we report two additional cases to emphasize the importance of obtaining an exposure history in a patient with perianal dermatitis.

Case reports

Patient 1

A 68-year-old man presented with a 1-year history of occasionally pruritic and bleeding patches of the buttocks, which were being treated as psoriasis. Prior use of econazole, triamcinolone, and calcipotriene creams provided no relief. On physical examination, the patient had an erythematous, scaling plaque on the elbow and erythematous patches with slight scale and fissures of the buttocks that extended into the intergluteal cleft. He was subsequently treated with fluocinonide ointment and improved initially, but relapsed.

Patient 2

A 57-year-old woman complained of perianal rash of 1-year duration. She used clobetasol, tacrolimus, and betamethasone/calcipotriene topical ointments with little improvement. She initially denied any exposure to chemicals. On physical examination, the patient had an erythematous, well-demarcated patch in the perianal intergluteal cleft that extended to the groin.

In both patients, punch biopsy of the perianal area demonstrated spongiotic psoriasiform dermatitis. The Thin-layer Rapid-Use Epicutaneous (T.R.U.E.) Test® (Allerderm Laboratories, Phoenix, AZ), a commercially available patch test series, revealed only MCI/MI allergy without allergy to quarternium-15, Balsam of Peru, fragrance mix, imidazolidinyl urea, or diazolidinyl urea. The MCI/MI concentration in the patch was 0.0040 mg/cm². It was discovered that MCI/MI was an ingredient in the moist wipes the patients were using. The moist wipes contained fragrance, which the patients did not react to on patch testing, and no other probable allergens. Upon discontinuation, the dermatitis resolved completely in both patients.


Methylchloroisothiazolinone/methylisothiazolinone (MCI/MI, commercialized as Kathon™ CG) is a preservative mixture with antibacterial and fungicidal properties used in various products, including moist toilet paper or baby wipes, moisturizing creams, shampoos, detergents, oil and cooling fluids, and paint, among other materials. It came into use as a preservative in the U.S. in the 1980s.

Moist toilet paper was initially popularized in Europe for infants, and its use expanded to an adult population. Early cases of MCI/MI-related allergic perianal and hand contact dermatitis were reported in European adults as confirmed by patch testing. Allergens in the moist toilet paper include Kathon™ CG as well as other allergenic preservatives (e.g., methyldibromoglutaronitrile) or fragrances like cinnamic alcohol [1, 2, 3, 4]. In these cases, the dermatitis resolved upon discontinuation of the moist toilet paper.

As utilization of moist toilet paper became more commonplace in the U.S., hand dermatitis in adults exposed to baby wipes containing MCI/MI, quaternium-15, and fragrance was identified [5]. Along with MCI/MI, DMDM hydantoin, 2-bromo-2-nitropropane-1,3-diol, and iodopropynyl butylcarbamate have been reported as potential culprits, causing dermatitis wherever the moist wipe was applied [6]. Furthermore, in a review in which various baby wipe brands available in Italy were analyzed for possible allergens, Zoli et al. observed that 91.3 percent of baby wipes contained a potential allergen, including phenoxyethanol, imidazolidinyl urea, and diazolidinyl urea [7].

Parameters that determine whether a person will develop a delayed hypersensitivity reaction to MCI include sensitization to the allergen that may occur with initial or multiple exposures, an ability to mount a hypersensitivity reaction, and the condition of the skin. For example, MCI/MI seemed to exacerbate underlying conditions like atopic dermatitis and seborrheic dermatitis; resolution of symptoms on discontinuation of use of the moist toilet paper was observed [2]. In addition, hand and perianal dermatitis and fungal infection resolved after discontinuing the moist toilet tissue paper, suggesting that one condition might predispose to the other by disrupting the integrity of the skin [4].

Discontinuing the use of products containing the suspected allergen is the mainstay of treatment. There is some evidence to suggest that glutathione-containing emollients inactivate methylchloroisothiazolinone/methylisothiazolinone [8]. Given the widespread use of this preservative in various everyday personal care products, including moist wipes, MCI/MI is another allergen to consider in the setting of perianal and contact dermatitis; eliciting an exposure history from the patient is essential.


1. Minet A, Eggers S, Willocx D, Bourlond A, Lachapelle JM. Allergic contact dermatitis from Kathon CG in moist toilet paper. Contact Dermatitis 1989: 21: 107-108. [PubMed]

2. de Groot AC, Baar TJ, Terpstra H, Weyland JW. Contact allergy to moist toilet paper. Contact Dermatitis 1991: 24: 135-136. [PubMed]

3. Guimaraens D, Condé-Salazar L, Gonzalez M A. Allergic contact dermatitis on the hands from chloromethylisothiazolinone in moist toilet paper. Contact Dermatitis 1996: 35: 254. [PubMed]

4. de Groot AC. Vesicular dermatitis of the hands secondary to perianal allergic contact dermatitis caused by preservatives in moistened toilet tissues. Contact Dermatitis 1997: 36: 173-174. [PubMed]

5. Guin JD, Kincannon J, Church FL. Baby-wipe dermatitis: preservative-induced hand eczema in parents and persons using moist towelettes. Am J Contact Dermat. 2001: 12: 189-192. [PubMed]

6. Fields KS, Nelson T, Powell D. Contact dermatitis caused by baby wipes. J Am Acad Dermatol. 2006: 54: S230-S232. [PubMed]

7. Zoli V, Tosti A, Silvani S, Vincenzi C. Moist toilet papers as possible sensitizers: review of the literature and evaluation of commercial products in Italy. Contact Dermatitis 2006: 55: 252-254. [PubMed]

8. Gruvberger B, Bruze M. Can glutathione-containing emollients inactivate methylchloroisothiazolinone/methylisothiazolinone? Contact Dermatitis 1998: 38: 261-265. [PubMed]

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