Vegetable oils: is there a correlation between food allergies and topical application?

The food allergies to vegetable oils stem almost exclusively from the presence of residual allergenic proteins derived from the oilseeds or oil-bearing fruits from which they are extracted. During refining, the majority of these proteins is removed, but infinitesimal traces may sometimes persist, particularly in partially refined or cold-pressed oils. These traces can be sufficient to trigger an immune response in certain individuals.

From an immunological standpoint, a food allergy is defined as a reaction of the immune system to a foreign protein. On first exposure, the body does not react immediately: it becomes sensitized, producing allergen-specific IgE antibodies. Upon subsequent exposure, these IgE antibodies recognize the protein in question and trigger a rapid inflammatory cascade: release of histamine, vasodilation, edema, itching, even severe systemic reactions such as anaphylaxis or Quincke’s edema. Thus, although refined oils are generally considered safe, a theoretical risk remains for the most sensitive individuals, including when the oil is applied to the skin.

To date, scientific evidence establishing a direct correlation between a food allergy and a skin reaction to the same vegetable oil remains limited.

In most cases, individuals with a food allergy to a vegetable oil can use it without experiencing an allergic reaction when applied topically, particularly when the oil is highly refined. Indeed, topical application to the skin exposes one to lower levels of allergenic proteins than ingestion, often insufficient to trigger a systemic immunological response.

However, caution remains warranted, as the medical literature reports a few isolated cases suggesting that cross-sensitization between the gastrointestinal and cutaneous routes is possible. For example, a 33-year-old individual experienced episodes of generalized urticaria after ingesting dishes containing sesame, but also upon cutaneous contact with a lipstick and a moisturizing cream containing sesame oil. In another case, a 30-year-old man suffered repeated urticarial episodes after consuming sesame-topped hamburgers. He subsequently developed immediate contact urticaria when handling a cosmetic oil that also contained sesame oil. Although rare, these observations indicate that cutaneous exposure to residual allergen traces can, in certain cases, trigger a reaction in highly sensitized subjects.

Thus, while a link between food allergy and cosmetic allergy remains plausible for vegetable oils, it remains relatively rare in practice. Nevertheless, as a precaution, we recommend consulting your primary care physician before any use and to perform a preliminary skin test on a small area of skin. This simple step allows you to verify individual tolerance and prevent any generalized reaction.

Certain plant oils exhibit a higher allergenic potential than others. Among them, peanut oil is the most frequently implicated. Indeed, peanut (Arachis hypogea) is known to be one of the most potent food allergens, with reactions that can sometimes be severe or even anaphylactic. Several studies have reported cases of urticaria and eczema flare-ups after topical application or ingestion of peanut oil, even when refined. However, other clinical trials indicate that a fully refined oil provokes no reaction, as the refining process almost completely eliminates the proteins responsible for the allergy.

The soybean oil and the sunflower oil are also considered to have allergenic potential, although allergic reactions upon contact or ingestion are rarer. Other oils warrant increased caution, notably sesame oil, sweet almond oil, hazelnut oil, or macadamia oil, all derived from tree nuts and thus more likely to be allergenic. Sesame oil, often used unrefined for its aromatic qualities, contains higher protein levels and has already been documented to cause cases of anaphylaxis.

Finally, certain oils present specific risks related to their chemical composition: those rich in salicylates, such as meadowsweet oil macerate, may be poorly tolerated by individuals sensitive to aspirin. Those from the Asteraceae family, such as calendula oil or safflower oil, are not recommended for people allergic to this botanical family.

• SAÏAG P. & al. Immediate hypersensitivity to sesame in foods and cosmetics. Contact Dermatitis (1998).

• CREVEL R. W. R. & al. Allergenicity of refined vegetable oils. Food and Chemical Toxicology (2000).

• GARVEY L. H. & al. Natural ingredients in cosmetic products – A suggestion for a screening series for skin allergy. Contact Dermatitis (2020).

• KOMARNYTSKY S. & al. The enigma of bioactivity and toxicity of botanical oils for skin care. Frontiers in Pharmacology (2020).

• GLAVAC N. K. & al. Vegetable butters and oils as therapeutically and cosmetically active ingredients for dermal use: A review of clinical studies. Frontiers in Pharmacology (2022).