Researchers identify most common fragrance additives related to allergic reactions

Researchers identified fragrance additives that are most likely to cause either immediate or delayed allergic reactions, according to data published in the Journal of the American Academy of Dermatology.

“Because fragrances can be absorbed into the body via the epidermis, the lungs or the gastrointestinal tract, fragrance allergies are common in the general population,” Nutchaya Amornruk, MD, of Chulalongkorn University in Thailand, and colleagues wrote. “Fragrance allergies can manifest clinically as an immediate or delayed-type reaction.”

Amornruk and colleagues continued that the diagnosis of fragrance allergies is complicated by the fact that the clinical spectrums are broad and numerous, although patch testing is a particularly reliable diagnostic tool.

To determine the prevalence of immediate or delayed reaction to fragrance, the researchers enrolled 291 patients from the contact dermatitis clinic at King Chulalongkorn Memorial Hospital in Bangkok in a prospective study for allergic contact dermatitis, 205 of whom were women.

The most common allergic reactions to standard patch test screening included fragrance mix I (19.59%), nickel sulfate (15.46%), methylisothiazolinone (10.65%), methyldibromo glutaronitrile (9.27%), balsam of Peru (8.25%), formaldehyde (8.25%) and fragrance mix II (8.25%).

Among the enrolled patients, 82 developed positive patch test reactions to one or more of the most common fragrance screening markers, particularly fragrance mix I (n = 57), balsam of Peru (n = 24), fragrance mix II (n = 24) and colophony (n = 21).

Additionally, the researchers found that a greater proportion of those who did vs. did not develop a positive patch test reaction to fragrance screening markers were women, aged older than 40 years and had hand dermatitis.

“However, in our patient cohort, there was no statistically significant correlation between fragrance allergies and physiological factors,” Amornruk and colleagues wrote, referring to sex, occupation, atopic dermatitis, age or locations on leg, hand or face.

The researchers then enrolled 40 of the original patients who tested positive for at least one fragrance screening marker into an analysis for delayed patch testing with 28 individual fragrance allergens. Thirty-eight of those patients had a positive reaction, nearly half for an immediate reaction and most (86%) for a delayed patch test.

The additives with the highest rate of positive immediate reactions included cinnamic aldehyde (40%), cinnamic alcohol (27.5%), sorbic acid (20%), coumarin (17.5%) and geraniol (12.5%).

The additives with the highest rate of positive delayed reactions included cinnamic alcohol (60%), cinnamic aldehyde (55%), ylang ylang oil (32.5%), balsam of Peru (30%) and isoeugenol (25%).

“Given that both fragrance substances were major components of spices and essential oils that were frequently used in a variety of Asian foods, beverages and personal care products such as mouthwash, it was expected that a high prevalence of immediate allergic reaction to these substances would exist in the Thai population,” the researchers noted.

The researchers also noted that, because they were unable to distinguish any relationship between patient factors and reactions, one possible explanation might be occupational risk that may expose patients to allergens on a regular basis, resulting in development of additional allergies.