Sensitization. You’ve probably heard the term around the aromatherapy community but you may not be quite sure what it means, how it occurs or how to reduce the risks? Well, let’s explore this for a moment. While there is an allergic reaction known as “respiratory sensitization”, we are going to address dermal sensitization in this article.
What is dermal sensitization to essential oils?
Dermal (skin) sensitization is a type of allergic reaction to a substance when it comes into contact with skin. It’s also known as a dermal hypersensitivity reaction or simply as sensitization. It can occur as an immediate allergic reaction or as a delayed allergic reaction.
Immediate allergic reactions occurs with the first dermal contact and presents with moderate to severe symptoms that may include redness, blotchiness, localized swelling, a rash, itchiness or what may appear to be a heat or chemical burn, sometimes accompanied by blistering. These symptoms are normally entirely localized at the spot of application/contact but they could present anywhere on the body where no contact with the substance was made. Immediate allergic reactions occur less frequently but they do happen more than some may realize.
Delayed allergic reaction typically occurs with the first exposure to a substance but usually presents with no symptoms or with only a slight or barely noticeable effect to the skin. Subsequent skin exposure to the same material, or to a similar one with commonalities, will produce a more severe inflammatory reaction with each exposure’s symptoms being worse than the last. These will present as inflammation, blotchiness, redness, itchiness, rash or may resemble a heat or chemical burn on the skin. Some individuals may also experience pain with a moderate to severe reaction. Again, these symptoms are usually localized to the area of contact but could happen anywhere on the body where no contact between the skin and the substance has occurred.
The problem with dermal sensitization is that once it occurs with a specific essential oil, the individual is most likely going to be sensitive to it for many years to come and perhaps for his/her lifetime. The individual may possibly never be able to have topical exposure to that essential oil or ones in the same family ever again.
How does dermal sensitization to essential oils occur?
Some individuals will be sensitive to a potential allergen while others will not so sensitization is unpredictable. While no one can predict who will have an adverse reaction to any given essential oil, there are some risk factors that need to be considered.
- Undiluted/Neat topical essential oil use
- Improperly diluted topical essential oil use
- Using known dermal sensitizers
- Frequent or overuse by topical application route
- Applying topically to broken skin or open wounds
How Can You Reduce the Risk of Dermal Sensitization to Essential Oils?
There are a number of proactive ways we can minimize our risks so we can enjoy using a wide array of essential oils for years to come.
DILUTE, DILUTE, DILUTE! Every essential oil, including lavender and other essential oils considered to be gentler, needs to be diluted in a fixed carrier oil, an oil based product such as a lotion/cream or a high fat content diluent such as very high fat milk for topical use. Water, witch hazel, epsom salts, and similar do not dilute or even disperse the essential oils. You still get them at full concentration with direct contact to skin and thus it’s undiluted/neat application. We cannot express the need to dilute essential oils with a proper medium enough.
Always properly dilute within skin safe ranges. All essential oils have individual recommended maximum dermal application rate set by the International Fragrance Association for use in cosmetic, commodity product and pharmaceutical applications. Some are as low as 0.01% while others have higher rates. These rates are determined by chemical composition and the evidentiary science related to human physiology and anatomy. For the use of essential oils for therapeutic purposes, Robert Tisserand and Rodney Young have researched and evaluated multiple sources of scientific research and evidence with essential oils to determine expert recommended safety advisories and safe dermal application guidelines for approximately half of the essential oils currently known or available in the world. This information and safe dilution guidelines are easily found in their widely trusted reference, Essential Oil Safety: A Guide for Health Care Professionals, 2nd Edition. There are also general dilution rate guidelines that are recommended throughout the aromatherapy community. For best practical topical application methods, try the lowest possible dilution percentage of essential oil to diluent, increasing in small increments to not exceed recommended maximum skin safe rates until desired results are achieved.
Avoid known skin sensitizers. There are several essential oils known to be mild to severe dermal sensitizers. Avoiding them is crucial and since there are essential oils that will usually give similar effects, it’s not hard to find an alternative. Some of those known to be sensitizers are:
Avoid applying the same essential oils every day for lengthy periods of time. The widely recognized and recommended safety method for regular topical application is 2 weeks on, 2 weeks off. Rotating the diluted essential oils you use daily every 7-14 days is a good way to reduce the risk of sensitization from overuse and frequent use.
Avoid applying essential oils (undiluted or diluted) to badly broken skin or open wounds. Not only is this ill-advised from a medical standpoint, possibly causing unnecessary discomfort or worsening the injury, it can also lead to sensitization that may last for the remainder of the person’s life. Wait until the body has done its job at starting to heal, use conventional allopathic medicine options and then when things are on the mend, you can proceed with diluted essential oils.
So as you can see, there are a number of things to consider when using essential oils topically and just as many measures you can take to avoid sensitization.
For more on allergic reactions and sensitization, see what many respected leaders in aromatherapy have to say:
“It has been said that it’s impossible to have an allergic reaction to essential oils, because they do not contain proteins, and only proteins can cause allergies. However, an allergen is a substance, protein or non-protein, capable of inducing allergy or specific hypersensitivity. Our immune system can’t recognize very small molecules such as those found in essential oils but, perhaps unfortunately, haptenation gets around this. The concept of a ‘hapten’ emerged from a series of articles by Landsteiner & Jacobs beginning in 1935, and is Greek for ‘to fasten’. Some essential oil constituents, such as cinnamaldehyde, can cause allergies because they are haptens. This means that they are ‘protein-reactive’; they bind with proteins in the skin. More specifically, they bind with peptides (short chains of amino acids) on the surface of Langerhans cells, and the Langerhans cells then migrate to local lymph glands, where the peptide-allergen complex is presented to T-lymphocytes. Antibodies are then created, and the next time the same hapten contacts the skin, an allergic reaction is almost inevitable.” – Robert Tisserand, “New Survey Reveals Dangers of Not Diluting Essential Oils”
Are Health Care Professionals Sensitizing or Poisoning Our Children? – Atlantic Institute of Aromatherapy
Mamas, Don’t Let Your Babies Grow Up To Be Sensitized – Atlantic Institute of Aromatherapy