Increased rates of fragrance allergy in fibromyalgia individuals tested with the Swedish baseline patch test series

Background: Contact allergy can manifest in a variety of ways clinically. Systemic contact allergy may occasionally present with pain in muscles and joints. Fibromyalgia is a chronic rheumatic disease characterized by pain and with virtually unknown aetiology. Objectives: The aim of this study was to investigate the contact allergy rates to the sensitizers in a baseline series and compare with corresponding rates in dermatitis patients and the general population. Methods: Patch testing with the Swedish baseline series was performed in 120 individuals with fibromyalgia. Fisher's exact test was used for pair-wise comparisons of contact allergy rates between the fibromyalgia group and two control groups, dermatitis patients and individuals in the general population. Results: Contact allergy was significantly more common in the fibromyalgia group compared to the general population concerning nickel and the fragrance markers Myroxolon pereirae and fragrance mix I. There were fewer allergic reactions to preservatives in the fibromyalgia group compared with the dermatitis group. Conclusions: Myroxolon pereirae and fragrance mix I represent besides fragrance allergy also allergy to flavouring substances which indicate that oral exposure to flavouring substances and hygiene products might be important for sensitization and possibly elicitation of systemic contact allergy symptoms in fibromyalgia individuals.