Can You Be Sensitive to Essential Oils?

Are we Sensitive to Essential Oils? Recently, a friend of mine, a new user of essential oils, called in a panic to tell me to check my phone. When I did there was a picture of her face swollen with red blotches.

“What happened?” I asked.

She stated it was a reaction to something she was using. After a lengthy discussion about which essential oils she had, how she was using them and how often, I determined the culprit was Boswellia caterii: frankincense. My friend had been using this particular oil several times daily without diluting it. She was using it on several moles which were a concern to her. She had read that Boswellia caterii: frankincense was a good choice for removing blemishes from the skin. While this oil was an excellent selection, using it neat (undiluted) on her skin was a poor choice. That plus the frequency of use had caused her to develop a sensitivity to the oil.

Depositphotos_27253757_l-2015Essential oils are extracted from plants, distilled, and when used properly have many therapeutic health benefits. Leaves, stems, roots, bark and flowers provide the plants with the oils they use for protection from diseases, extreme weather conditions, poor soil conditions, neglect and even predators. It stands to reason those same oils would be beneficial to humans as well. If the oils are grown in a favorable environment and distilled properly, the resulting oils offer many therapeutic benefits, such as relief from depression, combatting pathogens (harmful microorganisms), and a source of antioxidants which are needed to prevent and cure diseases. (Zielinski, 2016) (Bauer, 2016)

Mosby’s Medical dictionary tells us an allergic reaction is “an unfavorable physiological response to a substance (called an allergen) to which a person has been previously exposed and to which the person has developed antibodies” (Warren, 2014).That substance is not necessarily innately harmful, but may cause hypersensitivity in the person.

Allergens can present in the form of dust, pollen or dander. All allergens are proteins or polypeptides, which are large molecules of strings of amino acids. During the process of distillation only small molecules appear in the finished product, so the large molecules of proteins and polypeptides are not present. For this reason many humans are able to use with no problem the distilled oil product of plants to which they may otherwise have a sensitivity. For example someone who is allergic to cedar pollen may still be able to use the cedar oil distilled from the cedar tree with no issues. There are people in the essential oil industry who claim it is not possible to have sensitivities to essential oils since the proteins and polypeptides are absent in the oils after the process of distillation. There are many cases that indicate this is not true. (Warren, 2014)

One type of compound found in essential oils that may cause an allergic reaction are phenols. These include phenolic ethers, sesquiterpenes, which are known to break the blood brain barrier, and diterpenes. (Zielinski, 2016)

Some examples of essential oils that can contain these substances are:

  • Syzygium aromaticum: clove
  • Foeniculum vulgars: fennel
  • Ocimum Basillicum: basil
  • Cupressus sempervirens: cypress
  • Salvia sclarea: clary sage (Warren, 2014)

Some essential oils might cause an allergic reaction without the presence of proteins or polypeptides, if the oil contains a compound that can act as a hapten. “A hapten is a small, reactive molecule that, when combined with a skin protein, can cause the formation of antibodies and lead to an allergic reaction” (Warren, 2014). If essential oils become oxidized, they can then act as haptens and cause a burning sensation, redness of the skin, itching, or even blistering. Oils become oxidized if they are exposed to air, heat or light.

It is very important that essential oils are stored properly so that they do not become oxidized. Essential oils need to be stored in dark amber or colored glass bottles. They should be kept in temperature controlled, dark environments. Many essential oils have life spans that should be taken into consideration. It would be a good idea to date the bottle when the oil was purchased. Some recommendations for storing essential oils include:
• Store essential oils in dark colored glass bottles
• Have a temperature controlled environment – in the refrigerator, if necessary
• Use the smallest container possible to minimize contact with air


There are some oils that are susceptible to oxidation. They are:

  • Citrus bergamia: Bergamot
  • Piper nigrum: Black pepper
  • Cupressus sempervirens: Cypress
  • Foeniculum vulgars: Fennel
  • Boswellia carterii: Frankincense
  • Citrus x paradise: Grapefruit
  • Juniperus osteosperma: Juniper berry,
  • Citrus limon: Lemon,
  • Citrus aurantifolia: Lime
  • Melaleuca alternifolia: Melaleuca (Tea Tree)
  • Citrus sinensis: Orange
  • Rosa damascene: Rose Otto, Bulgarian,
  • Picea mariana: Spruce, Black
  • Tsuga Canadensis: Spruce, Blue

It is important to pay attention to the expiration time of certain oils. For example; Cymbopogon flexuosus: Lemongrass, Frankincense Boswellia carterii: Frankincense, Melaleuca alternifolia: Melaleuca, and Picea mariana or Tsuga Canadensis: Spruce oils should be discarded after 1 to 2 years, while Santalum album: Sandalwood and Pogostermon cablin: Patchouli will last 4 to 8 years. All other oils should be discarded after 3 years. (Warren, 2014)

It is fairly easy to determine if an oil has become oxidized. An oxidized oil will often lose its smell. Comparing the aroma with that of a freshly opened bottle is one way to tell if the oil still smells fresh. Citrus oils may become cloudy or sediment will form on the bottom of the bottle. The color of the oil may change. Certainly an oil that has been oxidized will lose or change its original properties. It will no longer be therapeutically effective, as well as possibly causing an allergic reaction. (Warren, 2014)

There are three skin reactions that may be induced by essential oils: Irritation, sensitivity (contact dermatitis) or photosensitivity. Symptoms of essential oil sensitivity may include: pain, swelling or tenderness of the skin; itchiness; hives, rash or boils; digestive upset and difficulty breathing.

Since oil sensitivities are not true allergic reactions, the user can try using a different oil with similar properties or change the application method. If the oil has been used topically, he can try diffusing the oil instead. Of course, the essential oil should be diluted with a carrier oil, such as coconut oil or any other vegetable oil before being topically applied. (DoTERRA blog, 2016)

Skin irritation will generally occur within minutes of exposure to the essential oil. The sensation felt is burning or the skin will feel warm to touch. A red wheal may appear. Any of these reactions may be caused by oils that are high in phenols, for example: Syzygium aromaticum: clove, Organum vulgare, CT Carvacrol: oregano or Thymus vulgaris, CT Thymol: thyme or aromatic aldehydes; Cinnamomum verum: cinnamon. If this type of reaction occurs the user should first dilute the area with a carrier oil and then wash with water and plain soap.

It is important to dilute first because washing first will drive the oil further into the skin. This kind of irritation can be avoided by diluting “hot” oils with a 2-5% strength.

Allergic contact dermatitis (ACD) develops over time with many exposures to an oil. I believe my friend had this type of reaction after applying too much undiluted frankincense too often. With the first few applications of the offending oil there would be no reaction. But with repeated exposure, it can even take years, symptoms may develop. Many things can cause this to happen. We just discussed overuse of an oil. Inadequate diet, chronic illness, the presence of other allergic conditions (asthma, hay fever), stress, advanced age or using oils that have been oxidized are some others. (Warren, 2014)

Depositphotos_86724466_l-2015Using high grade essential oils diluted with a carrier oil is vital to the prevention of skin irritations or other symptoms to appear. Essential oils can be altered with synthetic chemicals, similar lower-grade oils, water, or even vegetable oil. This is done to provide oils that are perfume grade and can be used for soaps and lotions, or to produce products that are lower in cost. Some pure essential oils, like Rosa damascene: rose or Citrus aurantium bigaradia: neroli can be expensive, but diluting it with adulterants will make them more affordable. However, if you are using adulterated oils you may experience skin irritation as well as disappointment in the therapeutic properties. (Center for Spirituality an Healing)
Certain essential oils will cause photosensitivity. Photosensitivity or photo toxicity is a skin reaction at the site of oil application that may result in a darkening of the skin, but can also cause blistering burns. This is caused when there is an interaction between the skin, a component in the essential oil, and UV photons.

Furanocoumarins is the main chemical component in essential oils that will cause photosensitivity. Citrus oils that have been cold pressed contain these chemicals, including:

  • Citrus bergamia: Bergamot
  • Citrus limon: Lemon
  • Citrus aurantifolia: Lime
  • Citrus x paradise: Grapefruit
  • Citrus aurantium or Citrus sinensis: Orange (Warren, 2014)

However, if these oils are instead prepared with steam distillation, the chemicals that cause this sensitivity are not always present. To avoid irritations from photosensitivity follow these guidelines:
• Avoid exposure to UV light 12 to 18 hours after applying citrus oils.
• Avoid exposure to UV light for 72 hours after applying bergamot.
• Use Citrus bergamia: bergamot in the diffuser only, not topically.
• Avoid using photosensitizing oils on your skin if your skin is exposed to UV light.
(Center for Spirituality and Healing, 2016)

“A mucous membrane irritant will produce a heating or drying effect on the mucous membranes of the mouth, eyes, nose, and reproductive organs” (Safety/National Association for Holistic Aromatherapy). Essential oils should not be added to a bath without first being placed in a dispersant, such as milk or vegetable oil. The following list includes oils that would be considered mucous membrane irritants according to NAHA.

  • Pimento racemose: Bay
  • Carum carvi: Caraway
  • Cinnamomum zeylanicum: Cinnamon bark or leaf
  • Syzygium aromaticum: Clove bud or leaf
  • Cymbopogon citratus: Lemongrass
  • Mentha x piperita: Peppermint
  • Thymus vulgaris: Thyme ct. thymol

So the question becomes: Are essential oils safe to use? Certainly there are many factors to take into consideration. In general, it is safe to say that when used appropriately essential oils are safe to use. For someone who is unsure or has had allergic reactions to substances in the past, it would be prudent to perform a patch test on a small area of skin. This is very easy to do, and it will provide peace of mind to those who are unsure.
To conduct an essential oil patch test mix 1 to 2 drops of essential oil with 3 to 6 drops of a carrier oil, such as fractionated coconut oil and apply to an unexposed area of skin. The abdomen or inside the elbow are good choices. You can cover the area with a band aid if you wish. After several hours the oil will have fully absorbed into your skin. If there is any redness, burning, itching or other symptoms, then you most likely have a sensitivity to that oil and should avoid its use. As stated earlier, you can then look for an oil with similar therapeutic properties to use instead. On the other hand, if no symptoms are apparent the diluted oil should be safe to use. (AromaWeb, 2016).
adult helping senior in hospitalAge, weight, and size of the user is another area to consider. Certainly for children or seniors, who may have lower tolerances, the doses should be lowered. There are many guidelines available to find the proper dosage. Betula alleghaniensis: birch, Gaultheria procumbens: wintergreen, or Mentha x piperita: peppermint oils should never be used on children, since those oils contain methyl salicylate, which is unsafe for children. An adult male would receive a larger oil dose, whether the inhalation or topical method is used, than a smaller female or a child. (DoTERRA blog, 2016).

Inhalation is the oldest and safest form of essential oil use. During diffusion the oils are at a high level of dilution. Obviously, this is the safest way to use essential oils. However, if any symptoms arise the diffuser should immediately be turned off. If the cup and breathe method is used or the oil is inhaled from an open bottle, the oil is carried directly into the respiratory and the mucous membranes. Then there would be a greater chance of a sensitivity occurring. Again, if symptoms occur the oil should no longer be used. (Zielinski, 2016).

Topical application of essential oils is a more direct method of dispersing oils into the body, however, the oil is absorbed through the layers of the skin. Those epidermal layers act as barriers, so this is not as direct an oil use method as inhalation. (Zielinski, 2016) One should always dilute with a carrier oil when applying oils topically. With essential oils it is always wise to remember that a little goes a long way. It can be easy to over use oils during topical use. (DoTERRA blog, 2016)

If used properly essential oils are safe. If safety precautions are followed, appropriate doses are abided by, and therapeutic grade oils are used, there would be few, if any, side effects. Age and health of the user should also be a consideration. Essential oils are a safe and natural means of preventing and curing many ailments, as well as reducing the intensity of symptoms of others.


AromaWeb. Essential Oil Skin Patch Test. Accessed August 28, 2016.

Brent A. Bauer. What Are the Benefits of Aromatherapy? The Mayo Clinic. Accessed August 28, 2016.

DoTERRA International. Current State of Essential Oil Toxicity Research Blog [Internet]. [cited 2016 September 1].

National Association for Holistic Aromatherapy. Exploring Aromatherapy. National Association for holistic Aromatherapy. Accessed September 1, 2016.

Totilo, R. Aromatherapy Certification Program, Level 1. St. Petersburg, Florida. Aroma Hut Institute. 2015.

University of Minnesota. Are Essential Oils Safe? Center for Spirituality & Healing and Charlson Meadows. Accessed August 28, 2016.

Warren K. Aromatherapy Blog [Internet]. Waco: Kristen Horner Warren. 2004 Oct – [cited 2016 August 28]. Available from:

Zielinski, E. The Great Aromatherapy Debate Blog [Internet]. Eric Zielinski. 2016 August – [cited 2016 September 3]. Available from: