PRAGUE – Reliance upon the time-honored tools for diagnosis of contact allergy due to fragrances will cause physicians to miss many cases, Dr. David E. Cohen said at the annual congress of the European Academy of Dermatology and Venereology.

"The old fragrance mix – fragrance mix I – and the use of balsam of Peru as fragrance screening tools really won’t capture contact dermatitis involving allergens to more modern fragrances," cautioned Dr. Cohen, professor and vice chair of the department of dermatology at New York University.

"I remember my grandmother always smelling like rosewater and naphthalene – like mothballs and rosewater. But we don’t smell like that anymore. Now we tend to use more botanical extracts. We see tea tree oil and jasmine appearing in our personal care products, and if we don’t test for those more contemporary fragrances, we will miss a very important source of contact dermatitis," he continued.

That’s why fragrance mix II (FM II) was developed. FM II has been incorporated into the North American Contact Dermatitis Group’s standard screening tray. It is not, however, part of the widely used T.R.U.E. (Thin-Layer Rapid Use Epicutaneous) test, nor is it included in the European standard screening series.

Multiple studies have documented that a substantial proportion of patients with allergic contact dermatitis will react only to the newer fragrances, and not to FM I or balsam of Peru. For example, a multicenter Hungarian study published earlier this year found that of 565 patients patch tested because of skin symptoms provoked by scented products, 17% exhibited contact hypersensitivity to one or more components of FM II. Moreover, 48% of FM II–positive patients reacted only to FM II, not FM I, balsam of Peru, or other test materials (Dermatitis 2012;23:71-4).

Similarly, a Mayo Clinic study of 945 patients patch tested using both the standard screening tray with FM II and the T.R.U.E. test found that 49% of patients reacted to one or more preservatives and 31% reacted to at least one fragrance or botanical additive. However, the T.R.U.E. test didn’t capture 23% of patients with a preservative allergy and 11% of those with a fragrance or botanical allergy (J. Am. Acad. Dermatol. 2010;63:789-98).

Fragrances pose one of the greatest challenges in the field of contact dermatitis. That’s because there are roughly 3,000 fragrance chemicals utilized in personal care products and cosmetics, and at least 100 of them have been described as causing contact dermatitis in patients. It can be difficult to assess the clinical relevance of positive patch test reactions because physicians don’t know what’s contained in North American fragrances. The fragrance industry is lucrative, secretive, and self-regulated.

Fragrance allergy is on the rise in children and adolescents, probably because they are being exposed to an onslaught of fragrance chemicals at a younger and younger age.

"When I grew up there was a bar of soap in the shower and, if we were lucky, shampoo; and if there was no shampoo we used the bar of soap. I have 19- and 17-year-old daughters, and if you go into their bathroom there are four different shampoos and three conditioners. There are things with glitter in there, and moisturizers and cosmetics, most of which I don’t even know what they’re for. All of them are fragrances. Folks are starting their exposure when they’re 7 and 8 years old. That was never the case before," said Dr. Cohen, who is also director of occupational, environmental, and allergic dermatology at the university.

The commercially available six-ingredient FM II panel is a 14% concentration composed of citronellol 0.5%, hydroxyisohexyl 3-cyclohexenecarboxyaldehyde (Lyral) 2.5%, hexyl cinnamal 5.0%, citral 1.0%, coumarin 2.5%, and farnesol 2.5%.

A long-standing point of contention has been the question of whether patients with atopic disease are more likely than nonatopic individuals to experience contact sensitivity, or less. The latest evidence suggests patients with asthma or severe atopic dermatitis have an overall lower prevalence of contact sensitization compared with nonatopic controls, with one striking exception.

In this very large study conducted by investigators at the Danish National Allergy Research Center, Copenhagen, an inverse association was found between atopic disease and contact allergy to metals and all groups of chemicals ... except fragrances. The prevalence of contact sensitization to fragrances was significantly higher in patients with atopic dermatitis than in controls. The investigators recommended that patients with atopic dermatitis be instructed to avoid scented moisturizers (Allergy 2012;67:1157-64).

The Danes found that patients with severe atopic dermatitis were 30% less likely than controls to be patch test–positive for contact sensitivity overall, whereas mild to moderate atopic dermatitis did not suppress contact sensitization. Again, fragrances constituted the exception: Not only did patients with severe atopic dermatitis have an increased prevalence of contact sensitization to fragrance chemicals, those with mild or moderate atopic dermatitis did, too, Dr. Cohen noted.

He reported having no financial conflicts.

b.jancin@elsevier.com

Contact dermatitis due to fragrances has morphed