Treating an itchy scalp can be vexing. That's because itching of the scalp can be due to a rash involving the scalp skin, or it can be due to scalp "dysesthesia" from cervical spine disease. Both are common, hence itchy scalp is a common complaint.
Does your scalp itch? If so, know that, of the rashes that can cause an itchy scalp, the most common is dandruff. Also called seborrheic dermatitis, dandruff can be so mild that you don't even know that you have it. No matter how mild or dramatic the dandruff, it can still cause a really itchy scalp.
For dandruff to cause your scalp to itch, you don't need heaps of scale on your scalp or the shoulder of your black shirt like you see on dandruff shampoo commercials. If there is any scale or pinkish redness on your scalp, or if you get a little "matter" under your fingernails when you scratch your scalp, you may very well have dandruff.
I treat a lot of scalp dandruff, and fortunately, I've found ways to control it conveniently. For starters, I recommend using a zinc pyrithione shampoo and a scalp scrubber to clean and treat your scalp when you wash your hair. The combination works great to combat scalp itch from dandruff/seborrhea. Check out my web page on scalp dandruff treatment to see how I treat dandruff in my dermatology practice.I specifically recommend my Foaming Zinc Cleanser (a great dandruff shampoo which can also be used on back, chest and ear dandruff - yes, it happens there too). The medicated pyrithione zinc in Foaming Zinc helps to control the overgrowth of Pityrosporum yeast, which plays a role in scalp dandruff. Even without dandruff, this yeast sometimes flourishes too much in scalp follicles causing itching and unwanted odor to the scalp. The full 2% concentration of pyrithione zinc is why this product works so much better than other dandruff shampoos in improving dandruff and scalp itch.
In addition, the perfect scalp scrubber is ambrosia for people with itchy scalp. I have my patients scrub the Foaming Zinc Cleanser onto the scalp using a scalp scrubber. The combination helps lift dandruff scale and helps the foam penetrate better into hair follicles and into the skin.
What are some of the common scalp rashes that cause itching other than dandruff?
Your scalp can also itch because you are allergic to hair care products. This is called allergic contact dermatitis of the scalp and is often seen as a scalp rash with redness and scale that extends to other skin areas where shampoo or product come into contact with skin. These can include the skin behind the ears and down the back and sides of the neck.
Figuring out if you have an allergy to a product may require a trip to the dermatologist. Hair care products are full of allergens including some of the most notorious allergens in the fragrance and preservative categories.
Other skin problems that can cause scalp itch include psoriasis, fungal scalp infections (ring worm of the scalp), head lice and a host of unusual rashes such as lupus, frontal fibrosing alopecia, lichen planopilaris and countless other unpronounceable conditions that require a trip to the dermatologist for diagnosis and therapeutic recommendations.
Itchy scalp from sunburn can happen too. Sunburn on the scalp usually involves just the top of the head, especially along the part line. There is no good treatment for a scalp sunburn because you just need to let the skin heal. It's best to prevent it in the first place by remembering your scalp needs sun protection just like the rest of your skin does.When you are in the sun, wear a really good sun hat. See my sun protection product collection for well-priced and easy to wear sun hats. I want your scalp sun-protected, which is why my sun hats are handy, practical and priced right.
Can washing too much or too little cause scalp itching?
Often, people think their itchy scalp is due to over or under-washing. Usually when I examine their scalp, I can see that the real cause is mild seborrhea - so mild they don't even know they have it. Seborrhea gets much worse when you don't wash your scalp enough. In fact, one simple treatment for seborrhea is just to wash more frequently.Conversely, the scalp has plenty of oil glands and holds up well to shampooing so that over-washing is rarely the cause of itchy scalp. Washing may dry out your hair shafts, but it's not usually a problem for the scalp skin itself. Remember though, shampoos can cause allergic reactions as I mentioned.
What is the cause of an itchy scalp that looks totally normal?
Scalp dysesthesia might be more than skin deep! Itchy scalp in the absence of any visible scalp skin rash has vexed dermatologists for years - until now! A retrospective study done on women who complained of scalp burning, itch, pain, and the feeling of "bugs crawling" on the scalp (dysesthesia means having odd sensations) in the absence of a scalp rash were found to have cervical spine disease.
What is scalp dysesthesia?
It means that scalp itch has joined the other regional dysesthesia syndromes (which I call "ghost" itch syndromes). These include brachioradial pruritus, genital pruritus and notalgia paresthetica. They are now all potentially connected to spinal cord abnormalities. Treatments to slow nerve impulses such as oral antidepressants and gabapentin may work when all else fails for severe cases. Overall, avoid reaching for anti-itch creams because they too can cause an allergic reaction.
Reference: Thornsberry LA and Engllish JC III. Scalp dysesthesia related to cervical spine disease. JAMA Dermatology, 2013 Feb; 149:200
Author: Dr. Cynthia Bailey M.D. is a Board Certified dermatologist practicing dermatology since 1987. She has done well over 200,000 skin exams during her career and authors the longest running physician written skin health blog in the world.