Have you been bedeviled by an itchy scalp? There are plenty of reasons why your scalp might itch. Lice are one possibility, of course, though they seem to be most common among children and people who live with or work with children. The other possibilities include a range of conditions, from dandruff to psoriasis. Seborrheic dermatitis (aka super-dandruff) may be one of the most common causes. What can you do to soothe it?
Soothing Your Itchy Scalp:
Q. Using old-fashioned amber Listerine for my itchy scalp worked wonders. Thank you for writing about this remedy.
Is It Infectious Dandruff?
A. The original maker of Listerine used to advertise its product for “infectious dandruff.” This had certain advantages from the perspective of the advertiser, since it fed social paranoia and made people even more anxious to get rid of (or cover up) their itchy flakes. But there’s no good evidence that dandruff is actually contagious or infectious.
That is probably why the FDA no longer allows this claim for Listerine. Nonetheless, dandruff and seborrheic dermatitis are characterized by flaking, redness and itching of the skin on the scalp or even on the face.
The Mysteries of Malassezia:
Both conditions are associated with an overabundance of normal skin yeast called Malassezia globosa (British Journal of Dermatology, Oct., 2011). This yeast requires fat to grow, so human skin provides excellent conditions for it. In fact, children start with a much wider range of skin fungi or yeast, but after puberty Malassezia globosa appears to dominate (Journal of Investigative Dermatology, online July 29, 2016). In addition to seborrheic dermatitis, Malassezia can cause a skin discoloration called tinea versicolor. Overgrowth with Malassezia is linked to skin itching and flaking.
Listerine to the Rescue:
While many dandruff shampoos can knock down Malassezia populations on the skin, the ingredients in Listerine also have antifungal activity. Veterinary researchers in Tehran isolated several Malassezia species (including M. globosa) from dogs with itchy skin (atopic dermatitis). They cultured the yeast and applied medicinal essential oils to see which were most helpful against these skin denizens. The most effective of these were Zataria multiflora, a wild herb from Iran that contains thymol and carvacrol, and Thymus kotschyanus, an Iranian species of thyme (Journal de Mycologie Medicale, March, 2016).
Thymol is an important constituent of both plants and an active ingredient in Listerine. It is reasonable to conclude that the thymol in Listerine contributes to its activity against common Malassezia.
Many people report that thoroughly soaking the scalp with Listerine before shampooing can control dandruff. Others have found that rinsing the scalp with amber Listerine after washing the hair relieves itching and flaking.
Our Guide to Hair and Nail Care includes a discussion of Listerine and many other home remedies for dandruff.