A patient who ingested large quantities of celery soup eaten before UV irradiation has been reported suffered for severe sunburn.
Bergamot oil (citrus bergamia) in eau de cologne had been described to cause hyperpigmented lesions.
A woman burned her one arm and leg after a 20-minute session on a sunbed, taken immediately after a sauna with lemon oil.
All the issues reported above are the side effects and contra-indication when using plants and essential oils. One of the safety consideration as mentioned in my previously article Essential Oils Safety and Toxicity is phototoxicity.
Today, we are going to delve further into this.
What is Phototoxicity?
Phototoxicity is a form of photosensitivity that is not depended on immunologic response.
It is the result of direct cellular damage caused by the reaction between photoactive agents and sunlight or ultraviolet (UV) light at the same time. This means, without the exposure to UV light, the reaction to phototoxic will not happened.
The exposure of photoactive agents are not limit to topical administration, it can via ingestion, inhalation or parenteral administration.
The degree of photosensitivity varies among individuals; the symptoms may include redness, inflamed, hyperpigmentation, exaggerated sunburn and skin blisters.
Furocoumarin (or furanocoumarin) is the chemical compounds that are common cause of phototoxicity.
Plants make furocoumarins mainly to defense against various types of predators such as viruses, bacteria, fungal spores, yeasts, and insects.
There are many different furocoumarins, examples include psoralen, methoxsalen, bergapten, and bergamottin.
Although furocoumarin is the cause photosensitization, but in the Eastern medicine, practitioners have applied poultices of plant juices containing furocoumarins to the whitened patches of skin seen in the disorder known as leukoderma or vitiligo. (Hoffmann, 2003)
According to Hoffmann, “as little as 1mg of 8-methoxypsoralen per square centimeter of skin can produce blistering after exposure to artificial UVA equipment equivalent to approximately 10 minutes of exposure to summer sunlight in the UK.”
Lists of Essential Oils Considered Phototoxic
The aromatic plant families contain most furocoumarins are Apiaceae and Rutaceae.
|Essential Oils||Botanical Latin Name|
|Bergamot (expressed)||Citrus bergamia|
|Bitter Orange||Cirtus aurantium|
|Grapefruit (expressed)||Citrus paradise|
|Lemon (expressed)||Citrus limon|
|Lime (expressed)||Citrus aurantifolia|
For details, please refer Tisserand, R & Young, R, 2013. Essential Oil Safety: A Guide for Health Care Professionals. Elsevier Health Sciences
Guidelines for Using Phototoxic Oils
- Avoid directly sun exposure, sun bathing or UV treatment after using the phototoxic oil. How long? It depends on the phototoxic oil concentration you use. For example: Tisserand and Young suggested that the skin treated with phototoxic oils at higher than those maximum use levels, should not expose to UV light for 12 – 18 hours. Sunbathing or UV tanning treatment suggested by Bensouilah and Buck is 24 hours. (Do research when you are using the oils, cause celery can caused sunburn for a patient after 3 days when undergone UV therapy.)
- Replace it with distilled or furocoumarin free oil. The furocoumarin are generally found in expressed citrus fruit oils but not in distilled citrus fruit oils. (Why? I think it is because furocoumarin are water soluble, distillation help to reduce the level of furocoumarin). For example, select the bergapten free bergamot oil which bergapten is removed from fractional distillation.
- Or avoid the phototoxic oil and replace with other oil which has the same therapeutic usage.
- Used within the limit suggested by the International Fragrance Association (IFRA) when formulating your skincare products.
“For leave-on products applied to skin areas exposed to direct sunlight, these limits include:
1.25% bitter orange peel expressed
4% grapefruit oil expressed
2% lemon oil cold-pressed
0.7% lime oil expressed
There are no restrictions for any of these oils in rinse-off products and products that are not applied to the skin.”
Bensouilah, J & Buck, P. 2006. Aromadermatology: Aromatherapy in the Treatment and Care of Common Skin Conditions. Radcliffe Publishing.
Klaus Peter Wilhelm, Hongbo Zhai, Howard I. Maibach, 2007, Dermatotoxicology, CRC Press
Hoffmann, D. 2003. Medicine Herbalism: The Science and Practice of Herbal Medicine, Innner Traditions.
Stewart, D., 2005. The Chemistry of Essential Oils Made Simple God’s Love Manifest in Molecules. Care Publications.
Tisserand, R & Young, R, 2013. Essential Oil Safety: A Guide for Health Care Professionals. Elsevier Health Sciences