Matthew Zirwas; Jessica Moennich


Dermatitis. 2009;20(2):106-110. 

In This Article


Included in the database were 179 shampoos; 170 of these products contained fragrance, which made fragrance the most commonly present allergen (Table 1). Of the nine products that did not contain fragrance, four contained potential allergens that are fragrance related; three of these four contained botanical ingredients, and one contained benzyl alcohol. Thus, there were five products in the database that were truly fragrance free and definitely safe for patients with fragrance allergy.

The second most commonly present allergen was cocamidopropyl betaine (CAPB). More than half the shampoos (95 of 179) contained this surfactant.

The third most common allergen was methylchloroisothiazolinone/methylisothiazolinone (MCI/MI), a nonformaldehyde preservative, which was present in 92 of the 179 products. A different class of preservatives, the formaldehyde-releasing preservatives, were the next most common allergens; 87 of the 179 products contained one of these allergens (68 contained dimethylol dimethyl [DMDM] hydantoin, 10 contained diazolidinylurea, 5 contained quaternium-15, and 4 contained imidazolidinylurea). Parabens were the next most common preservatives and constituted the seventh most common allergen overall, being present in 43 of the 179 products.

Propylene glycol, a water-soluble vehicle ingredient, was the fifth most common allergen; 68 of the 179 products contained this allergen. Vitamin E (tocopherol) was the sixth most common allergen, being present in 51 of the 179 products.

Benzophenones, which are ultraviolet light absorbers, and iodopropynyl butyl carbamate (IPBC), a nonformaldehyde preservative, were the eighth and ninth most common allergens, both being present in 10 products. Methyldibromoglutaronitrile/phenoxyethanol (MDBGN/PE), another nonformaldehyde preservative, was the tenth most common allergen, being present in six shampoos.