Plants causing skin reactions

Hello spring! Does it feel like the African sun sometimes forgets that spring exists as we abruptly hop from one season to the next? What often also comes on just as abruptly as the seasons is grass and other plant pollen causing irritation. Summertime for some means it is time to get outdoors again – enjoy the beach, or take a hike, run or cycle outdoors, or enjoy time in the garden. But for others, skin sensitivities rear its itchy head with a roar.

Plants are not just essential for its aesthetic beauty or nutrition. Plant extracts may also be found in essential oil products and products labelled as natural skin care products. Unfortunately, with all their beauty some plants may also cause skin reactions.

These often include:

Contact urticaria

Stinging nettles are the most common cause of contact urticaria. The reaction is due to sharp hairs on the plants, which create irritating substances. About three to five minutes after contact with the skin, the patient experiences redness, burning, numbness and itching. Most stings are self-limiting and does not require any treatment except painkillers.

Mechanical irritant dermatitis

Large spines on leaves or fruit (e.g. prickly pears) and thorns cause a penetrating injury into the skin. This may lead to a secondary infection. Thistle, tumbleweed, mulberry and fig tree leaves may all cause skin irritation. This can be treated by tweezers to remove small pieces of spines or thorns. You can also apply glue and gauze to the affected area. When it dries, pull it off to remove the thorns or spines.

Chemical irritant dermatitis

Calcium oxalate in daffodils can cause a chemical irritant dermatitis, and is most commonly experienced by florist and horticulturalists. Nitrile gloves can be worn to protect hands from possible skin irritation.

The famous Christmas flower, Poinsettias, may also cause this type of dermatitis. Capsaicin in hot peppers causes so called “chili burns” by activating nerves in the skin. The best home remedy for chili burns is to thoroughly wash your hands with soap and water. Then one hour of immersing the affected area in vegetable oil to remove the fat-soluble capsaicin.


This reaction occurs due to a combination of sun exposure and plant exposure. It is not an allergic reaction and anyone can experience it. Redness (for one to three days) and delayed hyperpigmentation (after one to two weeks) occur after exposure to certain plants. Plants such as limes, celery and rue are the most come causes of this type of irritation. Outdoor bartenders commonly develop hand dermatitis when they are squeezing limes for cocktails.

Photoallergic contact dermatitis on the other hand is a rare phenomenon. Prevention is the best treatment but if you have had been in contact with these plant irritants, remember to wash your hands with soap and water immediately may prevent a reaction.

Allergic contact dermatitis

Poison ivy, oak and sumac plants may cause this type of reaction. Urushiol is an irritating compound found in poison ivy that is absorbed into the skin. Some people can have an extreme reaction, while others remain unaffected. Although everyone should be cautious around poison ivy plants, it is best to avoid it. Flowers such as the dandelion, sunflower, daisy, dahlia and chrysanthemum can also cause this type of skin irritation.

If you come into contact with poison ivy, rinse the affected area with water immediately for at least ten minutes. Avoid soap as it can spread the plant resin. Topical steroids and calamine lotion can soothe a poison ivy rash.

How should you treat skin irritation from plants?

Minor itching, irritation or rashes can be treated with an oral antihistamine or mild topical steroid. If the rash doesn’t respond to this treatment, your best option is to consult a dermatologist.

In more severe reactions, where breathing or swallowing issues develop, go directly to the nearest casualty center.

In cases where the rash is extensive, a dermatologist may prescribe a strong topical steroid or a short course of oral steroids.

How can I prevent skin irritation from plants?

  • Wear protective clothing, for example gloves or long pants tucked into socks.
  • Apply a barrier cream containing quaternium-18 bentonite before going outdoors. This might help prevent plants from contacting the skin.
  • Avoid poisonous plants that are recognisable due to their three-leave groups. The rule is: “Leaves of three, let it be!”



Bolognia, Jean L., et al. Dermatology. Elsevier Health Sciences, 4th edition, 2018.