Hair Loss: Infectious Agents
Seborrheic dermatitis is first and foremost a skin condition, but it can
involve infection and temporary hair loss if the dermatitis is located on the
scalp or other skin areas. The dermatitis causes scaly, sometimes oily,
inflamed skin that can be itchy or even painful to touch.
This is an inflammatory condition that is not well understood, although
there does seem to be a genetic component and Caucasians, particularly of
Celtic descent, are most susceptible. Some newborns develop seborrheic
dermatitis when maternal androgens are passed from the mother to the baby
across the placenta. Conditions such as Parkinson's disease, head injury, and
stroke can also be associated with seborrheic dermatitis, and stress and
chronic fatigue can make it worse. Times of hormone fluctuation, such as during
puberty, can activate the onset.
In part, the trigger for seborrheic dermatitis may be androgen steroids. The
sebaceous glands attached to the hair follicles begin to produce a very rich
form of sebum. The sebum contains fewer free fatty acids and squalene but
increased amounts of triglycerides and cholesterol. The excess, rich sebum
production triggers the proliferation of skin flora. Yeast Pityrosporon
ovale (also called Malassezia furfur) has been shown to increase in
numbers with the intensity of seborrheic dermatitis. This excessive yeast
proliferation causes more irritation and inflammation.
Although all this inflammation is not specifically directed at the hair
follicle, if hair follicles are in the vicinity of the inflammatory cells then
they can be affected. Hair follicles find inflamed skin an unhealthy
environment in which to grow. Thus seborrheic dermatitis may non-specifically
cause diffuse hair loss.
Although seborrheic dermatitis can involve a proliferation of yeast,
seborrheic dermatitis is not infectious -- you cannot catch seborrheic
dermatitis. Where yeast is involved in seborrheic dermatitis it comes from the
affected individual's own skin. We all have yeasts of various types living on
our skin -- the problem in seborrheic dermatitis is that the yeasts may grow to
far greater numbers than normal.
There are several treatments for seborrheic dermatitis. The simplest
involves medicated anti-dandruff type shampoos to control the skin
proliferation and scaling. Several shampoos might be recommended for
alternating use on different days and each with its own particular
Shampoos for seborrheic dermatitis may contain sulfur, selenium sulfide,
zinc pyrithione, tar, salicylic acid, or oil of cade. These shampoos have been
available for many years. More recently azole-based shampoos (such as
ketoconazole [brand name: Nizoral]) have been made available over the counter.
All can be effective in treating seborrheic dermatitis.
Some dermatologists may also prescribe antibiotics to control the skin flora
and in doing so indirectly reduce the inflammation. The inflammation may be
directly treated using a corticosteroid cream or lotion to control the body's
immune response. Seborrheic dermatitis can be very persistent once it starts,
so staying with treatment is required and preventative treatment is useful even
when the symptoms are gone.
Published on March 1, 2010