D3.95 - Hidden in everyday cosmetics: Facial allergic contact dermatitis to fragrances

Introduction:

Allergic contact dermatitis (ACD) is a type IV hypersensitivity reaction affecting approximately 20% of the general population, with a significant impact on quality of life, particularly when involving the face. Fragrance allergens are among the most prevalent sensitizers, with positive patch tests (PT) in 5%-11% of tested patients. Linalool and limonene are the most frequently used fragrance terpenes in cosmetic products. These compounds are prehaptens that undergo autoxidation upon air exposure, forming hydroperoxides that are highly allergenic. Hydroperoxides of linalool induce positive PT in 7.7%-11.7% of patients, with the majority (69%) being clinically relevant.

Clinical case:

A 43-year-old woman, with a history of allergic rhinitis and no relevant occupational exposures, was referred to the Dermatology department for recurrent episodes of facial erythema, edema, pruritus and scaling, predominantly affecting the periorbital and malar regions. The patient reported symptom onset following application of her usual facial cream and serums, with resolution upon discontinuation of these products. PT was performed with the Portuguese baseline series (PBS), the fragrance series and her personal cosmetic products (two creams and one serum, containing citral, geraniol, limonene and linalool), with readings at 72 hours. Positive reactions were observed to balsam of Peru 25% petrolatum (pet) (+) and hydroperoxides of linalool 1% pet (++) from the PBS; geraniol 2% pet (+), citral 2% pet (++) and hydroperoxides of linalool 1% pet and 0.5% pet (++) from the fragrance series; and to one of her serums. PT to pure linalool was negative. ACD to fragrance allergens was diagnosed and allergen avoidance was recommended.

Conclusion: 

This case highlights the clinical relevance of oxidized fragrance allergens, particularly hydroperoxides of linalool, in cosmetic-induced ACD. The negative reaction to pure linalool with positive reaction to its hydroperoxides confirms that oxidized compounds are the primary sensitizers, underscoring the importance of including these allergens in PT to prevent missed diagnoses. Notably, PT was positive to only one of her personal products, likely reflecting differences in allergen concentration and degree of oxidation. Comprehensive PT, including fragrance series and the patient’s own cosmetic products, is essential for accurate diagnosis and appropriate management of cosmetic-induced ACD.