Coal tar is a topical, over-the-counter treatment approved by the Food and Drug Administration (FDA) to treat psoriasis. Coal tar is often used as an ingredient in creams, foams, soaps, and shampoos, sometimes in combination with salicylic acid. Doctors may prescribe coal tar at higher strengths than are available over the counter, or recommend that you use coal tar along with a prescription medication. Coal tar is frequently used to treat psoriasis on the scalp.
Coal tar should be used with caution in people currently experiencing a severe flare-up of psoriasis or a skin condition that covers a large percentage of their bodies. Coal tar may not be appropriate for women who are pregnant or breastfeeding.
Coal tar is a mild antiseptic and a keratolytic, or medication that promotes peeling. In cases of psoriasis, coal tar is believed to work by relieving itching, reducing inflammation, slowing the growth of cells, and softening scales, making them easier to remove.
How do I take it?
Always check with your doctor before taking a new medication, including over-the-counter medications.
Use products containing coal tar according to directions given by your doctor or found on the medication package. Do not exceed the recommended dosage. Note that products with different concentrations of coal tar are suitable for different parts of the body. For instance, stronger products are appropriate for the scalp, but not the face.
Avoid getting coal tar on broken skin, eyes, nose, mouth, anus, or genitals. Wash your hands after applying coal tar.
If the smell of coal tar shampoo bothers you, you can use a non-medicated conditioner after washing it out. However, do not use a non-medicated shampoo after applying coal tar shampoo.
In a 2010 article, researchers explored the use of coal tar 2 percent foam to treat psoriasis in challenging regions such as the scalp, the palms of the hands, and the soles of the feet. The authors concluded that coal tar foam was a beneficial new treatment.
Common side effects of coal tar may include staining, irritation, bruising, and thinning of the skin. Blood vessels may become more visible after using coal tar.
Coal tar can permanently stain light-colored hair, clothing, bedding, and jewelry.
Many people find the scent of coal tar unpleasant. You may smell like coal tar after using products containing it.
Coal tar increases your sensitivity to sunlight and your risk for sunburn for 24 hours after use.
At extremely high concentrations, coal tar can increase your risk of developing cancer. However, the FDA has stated that coal tar products are safe for humans at approved concentrations for over-the-counter products.
Seek medical help immediately if you experience symptoms of an allergic reaction such as trouble breathing, severe dizziness, rash, or itching or swelling of the face, tongue, and throat.