According to Dr. Harris Steinman, an allergy expert from South Africa, "Russian thistle can cause dermatitis in persons who come into direct contact with it. The dermatitis appears to be due only to mechanical irritation from plant floral bracts, which pierce the skin and stimulate an urticarial reaction." Urticaria is simply an itchy, stinging, hive-like rash that irritates the skin. Many types of thistles and plants cause similar reactions, and if you experience this you want fast relief.
Remove the Cause of Irritation
First, you will want to remove the cause of irritation; hopefully, you are no longer standing in the thistle patch. Next, you will want to remove any spines that may be lodged in the skin, as these will continue to cause irritation. It may be necessary to use tweezers. Plant saps and pollen can increase the reaction so you will want to wash with soap and water to remove these. This type of rash will go away on its own, usually within several hours to a day. However, if it is still quite painful, here are some more approaches to try.
An antihistamine will block the cause of the swelling and itching and make you more comfortable. Diphenhydramine, probably the most well-known antihistamine, can be purchased over the counter in various forms. If you take pills or a liquid by mouth, it will help ease your symptoms but may take several hours to have an effect. Applying a topical cream provides relief more quickly. Some antihistamines cause drowsiness and should not be taken if you need to remain alert. You should also avoid antihistamines if you are pregnant; check with your doctor if in doubt.
Hydrocortisone cream can also be purchased over the counter, and may prove helpful. It is a corticosteroid and functions by suppressing the immune response, thus reducing the itching and swelling.
Many people wish to avoid the use of drugs and medications, and choose home remedies. According to Grannymed.com, a mint poultice has a cooling effect that effectively reduces itching and pain. “Crush fresh mint and add cold water to make a paste; either apply directly to the affected area, or spread between two layers of muslin or gauze and apply to the rash. Wrap a towel or plastic around the poultice and pin it in place.” Aloe very is well-known for its soothing effect on irritated skin. You may use either a commercially prepared gel or fresh aloe vera. If using fresh, cut off the tip of a leaf and apply the gel that oozes out directly to the skin. Mixing a small amount of turmeric, which is known for its anti-inflammatory qualities, into the aloe vera gel may increase its effectiveness.