Posted by Joru (Northeast, US) on 12/14/2014
Sebhorreic dermatitis is often caused by an overgrowth of a type of yeast called Malassezia. Malassezia is different from candida and many other common yeasts in that it feeds on lipids (fats) rather than sugar/starch. Also it is a slow-growing, melanin-seeking yeast (melanin is the pigment in our skins which protects us from UV radiation).
In addition to causing scalp issues, it can infect the melanocytes of the skin (sometimes causing white hypopigmentation spots, burning, or itching), the ears (hearing issues), and the eyes (blurry vision).
Overgrowth occurs when conditions favor Malassezia growth over its microbial competitors. Such conditions include prolonged use of antibiotics, use of antifungals to which it is not susceptible, steroids or other immunosuppressants, medications which increase blood lipids; diets high in vegetable oils & animal fats, alcohol (with the possible exceptions of dry red wine and beer).
The best way to get it under control is to take both topics and internal measures that inhibit its growth and add "good flora" that keeps it in check. And to avoid the things that help it grow, when you can.
Some ideas include:
- Kimchi: kimchi is a fermented vegetable product full of "good bacteria" like lactobacilli. Buy the medium spicy kind (available at Whole Foods or elsewhere). Strain it and spray the juice on your scalp. Leave on for several hours or overnight. Repeat for several days or as needed. Eat the remaining part of the kimchi, some each day. This helps build competing flora.
- Increase your intake of veggies that are high in sulfur (so long as you tolerate them ok). These include: onions, garlic, asparagus, hoarseradish (esp. potent), broccoli & other brassica veggies. Also include ginger (antifungal properties).
- Minimize vegetable oils in your diet, including olive oil. Choose lean meats and low-fat dairy to minimize animal fats.
- Sourdough is possibly the best choice in the bread category, because it contains lactobacilli in add'n to some bread yeast. The lactobacilli ("good bacteria") are what give it the sour taste. Get it fresh from a bakery that doesn't use additives and keep it in the freezer.
- If possible, buy your food at farmer's markets rather than supermarkets. Food at the supermarket is almost by definition lacking in good flora. They use additives and irradiation to extend the shelf life. Fresh food from the farmer's market is more nutritious, and it contains live enzymes and more flora. Be sure to choose meat/dairy that were not given antibiotics or homones, as these promote the growth of fungi.
- Include some seafood and seaweed in your diet.
- Eat more fresh herbs and spices ... packed full of good stuff for you, delicious and flavorful, AND they help inhibit the growth of microorganisms.
Topical measures like shampoos can provide temporary relief of symptoms but since they don't affect Malassezia organisms that can be underneath the surface of the skin or scalp, they aren't getting at the root of the problem.