Types of Hair Loss : Infectious Agents

Ringworm

    Ringworm has nothing to do with worms, it is actually a fungal infection. Ringworm is first and foremost an infectious skin condition and can occur anywhere on the body, but if it develops on the scalp it can cause patches of hair loss. When it occurs on the scalp the professional term for ringworm is "tinea capitis". Ringworm is the same thing as athletes foot, and the same kind of fungal infection can affect the nails too. Ringworm of the scalp 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. The affected areas are often itchy, red and inflamed, 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, ringworm.

    Worldwide, the fungus Microsporum audouini is a very common cause of ringworm, but increasingly Trichophyton tonsurans can also cause tinea capitis, especially in Latin American countries. Other fungi that may cause tinea capitis include Trichophyton schoenleinii, Trichophyton megninii in Southern Europe and Africa, and Trichophyton violaceum in the Middle East. The fungus Microsporum gypseum can 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 resolve spontaneously and so no treatment may be given. Most commonly though an antibiotic called Griseofulvin 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 Griseofulvin gradually accumulates in the skin and hair. It especially likes to bind with keratin which is a key component of hair, skin and nails. The Griseofulvin blocks the fungus from infecting the keratin. More recently some fungi that cause tinea capitis have been showing some resistance to the drug Griseofulvin necessitating higher doses and longer courses of treatment. As an alternative to Griseofulvin, newer anti-fungal drugs like Terbinafine, Itraconazole, and Fluconazole can be prescribed.

Folliculitis

    Folliculitis is a term for focal inflammation of hair follicles. It looks like acne with little rings of inflammation surrounding the opening of a hair follicle. In the early stages of a folliculitis the hair fiber may still be present in the middle of the folliculitis, but as the folliculitis progresses the hair often falls out. When folliculitis is severe, the inflammation is so intense that it can actually permanently destroy the hair follicles, leaving little bald patches. There are forms of folliculitis which are non-infectious such as those caused by oils and greases applied to the skin that clog up the hair follicles, but f olliculitis is usually due to a bacterial infection. Particularly common is an infection of the hair follicles by Staphylococcus aureus. "Hot tub folliculitis" is caused by Pseudomonas aeruginosa which grows in inadequately chlorinated water. It is also possible to have viral, fungal, or yeast induced folliculitis involving Herpes simplex, Herpes zoster, Pityrosporum ovale, Trichophyton rubrum and other causative agents. Non-prescription topical antibiotics like bacitracin, mycitracin, or neomycin can be used to treat minor folliculitis. For more serious infections oral antibiotics such as erythromycin, or griseofulvin if the infection is fungal in nature, may be used.

Piedra 

    Piedra (Trichomycosis Nodularis) is a condition where the hair fibers are infected by a fungus. The visible indicator of a piedra infection is development of hard nodules on hair fibers. Indeed, Piedra is Spanish for stone. The nodules are a concretion of hyphae and fruiting bodies of the fungus, known as an ascostroma, from which the fungal spores are released. There are two basic typres of piedra, black piedra and white piedra, referring to the color of the nodules formed on the hair fiber. Black Piedra is due to the fungus Piedra iahortae and is mostly found in tropical countries while white piedra is due to Trichosporon beigelii and is found mostly in Europe and Southern parts of the USA.

    The infection may affect hairs of the scalp, body and genital areas. Usually the infection is relatively benign. In parts of Malaysia, the nodules of black piedra are considered attractive and traditionally women encouraged its growth by sleeping with their hair buried in the soil. However, when the infection is severe the fungus weakens the hair fiber making it easy to break off. This can result in a patchy - diffuse hair loss. Treatment generally involves shaving off affected areas or a topical application of salycylic acid, formaldehyde. White piedra is resistant to azole based antifungals, but this category of treatments is used for black piedra. Oral therapy with either ketoconazole or terbinafine has also been used.

Demodex Folliculorum

    There is a popular belief in some communities that Demodex folliculorum contributes to causing hair loss and that removing Demodex will enable hair regrowth. Demodex is a little worm-like creature that likes to live on skin and in hair follicles. Demodex feeds on dead skin and oils, so it particularly likes to live in hair follicles where there are lots of both. It is actually very common. We are born free of Demodex, but during childhood, through contact with others, our skin can become infected by Demodex. About 70% of adults have some Demodex in their hair follicles. For the most part, we never know they are there. They are benign, if repulsive, little creatures. The most common problem with Demodex is that they may cause irritation, particularly in the eyelashes. If you have itchy eyelashes it may be Demodex is the problem. However, this is as much as Demodex can do to you. It does not cause hair loss.

Seborrheic Dermatitis

    Seborrheic dermatitis is not an infectious disease, but it can involve infection. Seborrheic dermatitis is first and foremost a skin condition, but it can also involve temporary hair loss if the dermatitis is located on the scalp or other terminal-haired skin areas. The dermatitis presents as scaly, sometimes oily, inflamed skin that can be itchy or even painful to touch. This is an inflammatory condition the cause of which is not well understood, although there does seem to be a genetic component and Caucasians, particularly of Celtic descent, are most susceptible. It seems that 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. In part, the trigger for may be androgen steroids. Times of hormone fluctuation, such as during puberty, can activate the onset of seborrheic dermatitis. Seborrheic dermatitis can also be observed in some new born babies when maternal androgens are passed from the mother to the baby across the placenta. Conditions including Parkinson's disease, head injury, and stroke can also be associated with seborrheic dermatitis, and things like stress and chronic fatigue can make it worse.

    The excess, rich sebum production in seborrheic dermatitis can trigger 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 still be adversely affected. Hair follicles find inflamed skin an unhealthy environment in which to grow. Thus seborrheic dermatitis may non-specifically cause diffuse hair loss. This hair loss should be reversible with reduction of the inflammation intensity. Although seborrheic dermatitis can involve a proliferation of years it is important to point out that 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 treatment involves the use of 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 activity. 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 (Ketoconazole - Nizoral) have been made available over the counter. Other medicated shampoos may contain fluconazole. 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 immune response. Seborrheic dermatitis can be very persistent once it starts so persistence with treatment is required and preventative treatment is useful even when the symptoms are gone.