These Are the Essential Oils That Most Commonly Trigger Allergic Reactions

Essential oils are often hailed as natural wonders—some allegedly promote increased focus, while others soothe anxiety. But but not all EOs, as they're commonly referred to, were created equal. In fact, some frequently cause allergic reactions when they come into contact with your skin. Ahead, Melanie D. Palm, M.D., M.B.A, and board-certified dermatologist and cosmetic surgeon, explains which oils you should avoid and why.

Getty / Anatoliy Sizov

Related: These Beauty Brands Are Perfect for Those with Sensitive Skin

Why We React to Essential Oils

The answer to this question involves first understanding the differences between an allergic reaction and an irritant reaction. "Irritant reactions occur from higher concentrations of ingredients that aggravate the skin," Dr. Palm explains. This type can cause a local skin irritation that will resolve as soon as you remove the essential oil you are reacting to. "An allergic skin reaction, on the other hand, requires an immune response to an offending agent and thereby requires a repeat exposure—a process called sensitization."

You are more likely to experience an irritant reaction immediately, as opposed to an allergic reaction, which may occur days after exposure. Dr. Palm also notes that an allergic skin reaction is not reversible (and will gradually worsen every time you apply the product) and is more likely to occur on wet or open skin or if higher concentrations of an essential oil is used (since this exposes your immune system to a higher concentration of allergy-causing proteins in the essential oils).

Common Symptoms

The most common allergic skin reactions caused by essential oils are contact dermatitis, which manifests most commonly as an itchy rash, and contact urticaria, which triggers hives following exposure. "You can minimize the chance of developing an allergic contact dermatitis to an essential oil by following age-related safety guidelines and not using highly concentrated (no more than five percent, but many times, this should be much less) or undiluted essential oils," adds Dr. Palm, noting that they're often better received on hydrated skin (so go ahead and pop them in the bath).

Offending Oils

While you can have a reaction to nearly any oil if it prompts an immune response in your body, Dr. Palm says that Ylang-Ylang, lemongrass, cinnamon bark, tea tree, jasmine absolute, balsam of Peru, clover, and sandalwood are among the most common essential oils to illicit an allergic contact dermatitis. "However, a long list of essential oils can cause an allergic reaction, including bay oil, cassia oil, holy basil oil, lemongrass oil, lemon myrtle oil, massoia oil, may chang oil, Melissa oil, oakmoss absolute, and opoponax oil," she notes.

Determine Your Risk Level

"Once sensitization occurs, you will have a lifelong reaction to the allergic agent," Dr. Palm says. "Additionally, future exposures to the allergy-causing essential oil will cause more severe skin reactions." Those who fall within the "atopic triad"—or those with atopic dermatitis, eczema, seasonal allergies, and asthma—are much more likely to develop allergic contact dermatitis. Women are also more prone to these reactions than men, she says, due to an underlying hormonal cause, "which is likely a contributing factor to this difference."