Salicylates are chemicals found naturally in many plants and are also an ingredient of aspirin and other pain-relieving medications.
They are widespread in fruit and vegetables, as well as in health, beauty and household cleaning products. Salicylate sensitivity is not a classical allergy with immune system involvement, and is defined as a non-specific antigen-induced pseudo-allergic hypersensitivity reaction to salicylic acid and its derivates or chemically similar molecules. A postulated cause is an overproduction of leucotrienes (inflammatory mediators) and their metabolites. The existence of salicylate sensitivity is refuted by many allergy specialists, due to the absence of clear supporting or even contrary medical evidence. However, numerous suggestive case reports are encountered.
Frequency in population
The frequency of salicylate sensitivity is reported to lie between 2 to 40% of patients attending allergy clinics and between 2 to 7% of patients with gastrointestinal disorders, such as inflammatory bowel disease. The prevalence may be higher in patients with asthma or polyps in the nose.
The symptoms of salicylate sensitivity vary, but can be asthma-like, such as difficulty in breathing, wheezing, and can also include headache, nasal congestion, skin rash, hives and itching, swelling of the hands, face and feet, inflammation of the eyes, stomach pain and nausea. In severe cases, salicylate sensitivity can lead to anaphylaxis, a life-threatening reaction involving a severe drop in blood pressure, loss of consciousness, and organ system failure. Avoiding products that contain salicylates is the best prevention of a reaction.
Testing and diagnosis
Confirmation of salicylate sensitivity is based on extensive observation of dietary and other substance exposure and correlation with symptoms. A food and drink diary may be useful for this purpose and an elimination diet may be necessary to ascertain the main offending food. An exclusion of all salicylate containing products is neither feasible nor necessary, as the sensitivity often involves specific products and smaller quantities may in many cases be tolerated. We suggest consulting a specialist doctor or dietician for potential differential diagnosis and management.
No specific test exists for salicylate sensitivity, but elevated levels of methylhistamine in the urine may be a useful disease marker.
This entity remains medically unproven.
Individuals have differing sensitivity thresholds to salicylates and the intolerance does not necessarily involve the entire spectrum of salicylate-containing products. Many foods with high salicylate content also have high amine content.
Some examples of substances containing salicylate in higher concentrations include the following:
Fruit: Includes apples, apricots, avocados, dates, kiwi, peaches, figs, grapes, plums, cherries, grapefruit, prunes, and many berries, such as strawberries, blueberries, raspberries.
Nuts such as pine nuts, peanuts, pistachios, and almonds.
Vegetables such as alfalfa, cauliflower, chicory, cucumbers, mushrooms, radishes, olives, broad beans, eggplant, spinach, zucchini, broccoli and hot pepper.
Herbs, spices, and condiments such as dry spices and powders (e.g. aniseed, cayenne, curry, dill, thyme, white vinegar, Worcester sauce), tomato pastes and sauces, vinegar, soy sauce, jams and jellies, some cheeses.
Beverages such as coffee, wine, beer, orange juice, apple cider, regular and herbal tea, rum and sherry.
Some sweets, such as peppermints, licorice, mint-flavored gum, breath mints, ice cream, gelatin.
Health and beauty products: fragrances, perfumes, shampoos, conditioners, herbal remedies, lipsticks, lotions, skin cleansers, mouthwash, mint-flavored toothpaste, shaving cream, sunscreens, tanning lotions, muscle pain creams.
Medications and oral chemical compounds: Alka Seltzer, aspirin, acetylsalicylic / salicylic acid / salicylates, 5-ASA compounds (e.g. mesalazine), various non-steroidal anti-inflammatory drugs NSAIDs), artificial food coloring and flavoring, menthol and mint / peppermint / spearmint.
Further ingredients to watch out for and avoid: Aloe Vera, azo dyes, benzoates (preservatives), benzyl salicylate, BHA, BHT, disalcid, eucalyptus oils, oil of wintergreen, red dye (#40), salicylaldehyde, salicylamide, salsalate, yellow dyes (#5, #6).
Links to literature