Hair Loss: Infectious Agents
A number of infectious agents and infection-related conditions can
contribute to hair loss. Some common ones are described here.
Surprisingly, ringworm has nothing to do with worms, but is a fungal
infection that can occur anywhere on the body. If it develops on the scalp, it
can cause patches of hair loss and is known to doctors as "tinea capitis."
Ringworm is the same thing as athlete's foot, and the same kind of fungal
infection that can affect the nails too.
On the scalp, ringworm usually begins as a small pimple that progressively
expands in size, leaving scaly patches of temporary baldness. The fungus gets
into the hair fibers in the affected area and these hairs become brittle and
break off easily, leaving a bald patch of skin. Affected areas are often itchy,
red, and inflamed, with scaly patches that may blister and ooze. The patches
are usually redder around the outside with a more normal skin tone in the
center. This may create the appearance of a ring -- hence the name,
Worldwide, the fungus Microsporum audouinii is a very common cause of
ringworm, but increasingly Trichophyton tonsurans can also cause tinea
capitis, especially in the US and Latin American countries. Other fungi that
may cause tinea capitis include Trichophyton schoenleinii and
Trichophyton megninii in Southern Europe and Africa, and Trichophyton
violaceum in the Middle East.
The fungus Microsporum gypseum can also sometimes cause tinea
capitis. This fungus is common in soil and may be transferred to humans by
contact with infected animals. You can also get ringworm from pets that carry
the fungus, and cats in particular are common carriers. Ringworm is contagious.
It can be passed from one person to the next by direct skin-to-skin contact.
You can also catch ringworm through contact with contaminated items such as
combs, unwashed clothing, and shower or pool surfaces.
Treatment for ringworm varies depending on the particular fungus involved.
Some types of ringworm infection will go away spontaneously and no treatment is
given. However, most commonly, griseofulvin, an anti-fungal, is used.
Griseofulvin is very effective against fungi in hair and skin but it is not so
good at treating yeast or bacterial infections. The drug gradually accumulates
in the skin and hair. It especially likes to bind with keratin, which is a key
component of hair, skin, and nails, and blocks the fungus from infecting the
More recently, some fungi that cause tinea capitis show some resistance to
the drug, which means higher doses and longer courses of treatment. As an
alternative to griseofulvin, newer anti-fungal drugs like terbinafine,
itraconazole, and fluconazole can be prescribed.