Myths Relating MPB and Other Skin Disorders

No. It doesn't. Psoriasis is a common scaling skin disease that affects around 1 to 2 per cent of the population. Scalp psoriasis occurs in at least half of all patients afflicted with psoriasis. Psoriasis can range from very mild with fine scaling to very severe with thick, crusted plaques and the condition can be both distressing and cosmetically disfiguring. However, psoriasis does not generally cause permanent loss of hair. This is because psoriasis involves the epidermis and not the dermis. The dermis is where the hair follicles develop. Any hair loss that psoriasis may cause would be separate from male pattern baldness.

Psoriasis itself will not cause the hair to fall out. However, very thick scales in the scalp can entrap hair and as you attempt to remove the scales, the hair shafts can be pulled out in the process. Psoriasis can contribute to the hair being 'brittle, thin, split ended, and difficult to manage', but the psoriatic process does not harm the hair follicles themselves. Sometimes medicated shampoos and other topical medications can adversely affect the hair. Any alcohol-based solution can irritate areas of psoriasis, so patients would need to be judicious in their use. Unfortunately, there is no cure for psoriasis. But there is good treatment. You can get reliable information at many non-commercial websites such as http://www.nlm.nih.gov/medlineplus/psoriasis.html or http://www.psoriasis.org/home/

Seborrheic dermatitis affects areas with high densities of large oil glands, e.g. the scalp, behind the ears, eyebrows, etc. Despite the name, the composition and flow of sebum are usually normal. As explained below, seborrheic dermatitis does not cause permanent hair loss. Most dermatologists (and all the standard dermatology textbooks) say, "seborrheic dermatitis does not cause hair loss". The inflammation that may occur with seborrheic dermatitis is thought to be due to the body's reaction to a yeast in the scalp (Pityrosporum) and to products that break down oil.

Temporary hair loss can occur in the areas of seborrheic dermatitis because the inflammatory changes are unhealthy for the hair follicles. However, when the seborrheic dermatitis improves, the hair grows back again. This is different and unrelated to the type of 'hair loss' that occurs with MPB. In MPB, hair also grows back again, but the size of the hair shaft may be significantly reduced. It is not unusual to experience seborrheic dermatitis and MPB at the same time and neither condition exacerbates the other. Sebum does contain concentrated levels of DHT, but since the sebum on the scalp is very superficial to the androgen receptors at the level of the hair follicles, which are deep in the dermis, it plays no role in initiating the chain of events, which results in miniaturizing the hair follicle in the process of MPB.

Wrong. When DHT attaches to the androgen receptor sites at the hair follicle, it triggers a very complicated chain of events that results in the miniaturization of the follicles with a surrounding inflammatory response. When the pathologist refers to microscopic inflammatory changes, he is describing an autoimmune response, not any kind of infection, which is defined as an invasion by and multiplication of pathogenic microorganisms in a body part or tissue. MPB is not due to any kind of infection.

No. It won't. Superficial irritations of the scalp will not cause any injury to your hair or to your hair follicles. There are up to 10% of patients who have an adverse effect on the scalp due to the applications of minoxidil solutions containing propylene glycol, which comprises 50% of the base of many 5% minoxidil solutions. The growing hair follicles are embedded deep in the dermis of the scalp and are not affected by any superficial irritation to the scalp.