Oxidized limonene and oxidized linalool - concomitant contact allergy to common fragrance terpenes

BACKGROUND

Limonene and linalool are common fragrance terpenes. Both oxidized R-limonene and oxidized linalool have recently been patch tested in an international setting, showing contact allergy in 5.2% and 6.9% of dermatitis patients, respectively.

OBJECTIVE

To investigate concomitant reactions between oxidized R-limonene and oxidized linalool in consecutive dermatitis patients.

METHODS

Oxidized R-limonene 3.0% (containing limonene hydroperoxides 0.33%) and oxidized linalool 6% (linalool hydroperoxides 1%) in petrolatum were tested in 2900 consecutive dermatitis patients in Australia, Denmark, Singapore, Spain, Sweden, and the United Kingdom.

RESULTS

A total of 281 patients reacted to either oxidized R-limonene or oxidized linalool. Of these, 25% had concomitant reactions to both compounds, whereas 29% reacted only to oxidized R-limonene and 46% only to oxidized linalool. Of the 152 patients reacting to oxidized R-limonene, 46% reacted to oxidized linalool, whereas 35% of the 200 patients reacting to oxidized linalool also reacted to oxidized R-limonene.

CONCLUSIONS

The majority of the patients (75%) reacted to only one of the oxidation mixtures, thus supporting the specificity of the reactions. The concomitant reactions to the two fragrance allergens suggest multiple sensitizations, which most likely reflect the exposure to the different fragrance materials in various types of consumer products. This is in accordance with what is generally seen for patch test reactions to fragrance materials.

Sorbitan sesquioleate; a rare cause of contact allergy in consecutively patch tested dermatitis patients

BACKGROUND

Sorbitan sesquioleate (SSO) has been added to fragrance mix I (FM I) as an emulsifier since the 1990s. Being a contact allergen itself, SSO has the potential to cause false-positive reactions to FM I. Recent results obtained with selected FM I-positive patients have shown that 5% have concomitant positive reactions to SSO.

OBJECTIVES

To investigate the 5-year prevalence of contact allergy to SSO and evaluate the importance of SSO allergy when patch test results for FM I are interpreted.

METHODS

This was a retrospective database study of consecutively patch tested eczema patients (n = 4,637) from 2010 to 2014. All patients were tested with our baseline series including FM I and SSO 20% in pet.

RESULTS

Sensitization to SSO was identified in 9 (0.2%) patients. The proportion of FM I-positive patients with concomitant positive reactions to SSO was 1.4%.

CONCLUSIONS

SSO is a rare cause of contact allergy, with a 5-year prevalence of 0.2% in consecutively tested patients. Contact allergy to the emulsifier does not play a major role when the overall frequency of contact allergy to FM I is evaluated. However, to correctly diagnose individual patients, concomitant patch testing with FM I and SSO is encouraged.