Perfume is a complex mixture of natural and synthetic sweet-smelling constituents. More than 5,000 compounds are known to be in used in the making of perfume. Certain compounds evaporate and become airborne thus lending perfume its smell.
Patients with allergic airway diseases can have exacerbations of their symptoms upon inhalation of these perfume compounds. For example, patients with allergic rhinitis that is not controlled can start sneezing and develop nasal congestion after smelling perfume. Patients with uncontrolled asthma may develop chest tightness and wheezing.
In a study published in the Annals of Allergy, asthmatic exacerbations after perfume challenge occurred in 36%, 17%, and 8% of patients with severe, moderate, and mild asthma, respectively. These symptoms were mainly assumed to be due to the irritant effects of perfumes.
However compounds found in perfumes can also cause allergic sensitization. The most common cause of cosmetic allergy is allergic contact dermatitis to the fragrance found in cosmetics. Recent estimates show that 1-4% of the general population are sensitized to ingredients of the fragrance mix. Allergy to fragrance in cosmetics occurs predominantly in women with facial or neck eczema. It can also present as itchy red patches where perfume are usually dabbed on, such as on the wrists or behind the ears.
Some patients with severe allergy to fragrance have been reported to develop to skin rash after eating spices such as cinnamon, cloves and vanilla which containing similar compounds found in fragrances. This is a situation where the person with allergic contact dermatitis to a compound has their rash exacerbated after eating certain cross reactive foods.
For patients who have allergies to perfume, they should also carefully read product labels. The use of the term unscented does not mean that it is fragrance free; they should instead choose a fragrance-free product which is typically free of allergenic fragrance.