When people develop an itchy scalp, they often look to their local drugstore shampoo aisles for help, with more than a billion dollars spent annually on medicated shampoos, according to Dr. Stuart Maddin, editor of the "Skin Therapy Letter." There are many different types of shampoos to choose from, each with different ingredients and varying benefits. Determining which one is right for you may depend upon its effects and your specific condition.
Identification
San Diego dermatologist Jeffrey Benabio, author of The Derm Blog, identifies dandruff as the leading cause of scalp itching. Dandruff results from a yeast overgrowth on your scalp, which leads to inflammation and itching. If your scalp is also red and flaky, it's called "seborrheic dermatitis" -- not to be confused with a similar condition, psoriasis, which produces thicker, drier scales and also shows up on other parts of your body. Additional causes of itchy scalp can include allergic contact dermatitis, which is an allergy to an ingredient in your hair-care products; hair follicle inflammation or infection, usually accompanied by acne-like bumps; and in rare cases, diseases such as discoid lupus, alopecia and dermatomyositis. Scalp itching can even be caused by not washing your hair frequently enough, which leads to a buildup of oil.
Shampoo Types
Various medicated shampoos are available over the counter to help treat scalp conditions, containing ingredients such as: zinc pyrithione, an antibacterial and antifungal agent that can reduce the fungus on your scalp causing dandruff and seborrheic dermatitis; coal tar, a byproduct of the coal manufacturing process, which slows the rate at which skin cells on your scalp die and flake off; salicylic acid, a scrubbing agent that eliminates scaling; selenium sulfide, which slows your skin cells from dying; ketoconazole, a broad-spectrum antifungal agent; and tea tree oil, an antiseptic, antibiotic and antifungal agent that comes from the leaves of an Australian tree.
Considerations
You should always leave any medicated shampoo on for at least five minutes to give the ingredients enough time to do their job. Since all skin types are different, what works for one person may not work for another, and you may need to try more than one product before you find the most effective one. The Mayo Clinic recommends using one type of shampoo daily until your symptoms are controlled, then cutting back to two or three times a week. If that product starts to lose its effectiveness, you can alternate between two different types of medicated shampoos. If these measures don't work, you may need a prescription-strength shampoo or steroid lotion from a doctor.
Prevention
It helps to shampoo frequently, especially if you have an oily scalp, and also to cut back on styling products such as sprays, gels, mousses and waxes, which can build up on your scalp and make it oilier. The Mayo Clinic also suggests eating a healthy diet with recommended daily allowances of zinc, B vitamins and healthy fats to prevent dandruff, and getting small amounts of sunlight. Columbia University Health Services recommends avoiding scratching your scalp, applying cool, wet compresses, using a soaking solution made from uncooked oatmeal or baking soda and avoiding perfume or dyes in your hair-care products. Look for hypoallergenic formulas instead.
Warning
According to an article by J. Shapiro and S. Maddin in "Clinics in Dermatology" published in 1996, coal tar, found in some medicated shampoos, has been linked to potential problems with fetal development and could be a cancer-causing agent.
