Alopecia

Alopecia (, from Classical Greek ἀλώπηξ, alōpēx) means loss of hair from the head or body. Alopecia can mean baldness, a term generally reserved for pattern alopecia or androgenic alopecia. Compulsive pulling of hair (trichotillomania) can also produce hair loss. Hairstyling routines such as tight ponytails or braids may also induce a form of alopecia known as Traction alopecia, as can hair relaxer solutions, and hot hair irons. In some cases, alopecia is due to underlying medical conditions, such as iron deficiency.

Generally, hair loss in patches signifies alopecia areata. Alopecia areata typically presents with sudden hair loss causing patches to appear on the scalp or other areas of the body. If left untreated, or if the disease does not respond to treatment, complete baldness can result in the affected area, which is referred to as alopecia totalis. When the entire body suffers from complete hair loss, it is referred to as alopecia universalis. It is similar in to the effects that occur with chemotherapy.

Signs and symptoms
When examining the scalp, the distribution of hair loss, presence and characteristics of skin lesions, and the presence of scarring should be noted. Part widths should be measured. All abnormalities should be noted.

In male-pattern hair loss, loss and thinning begin at the temples and either thins out or falls out. Female-pattern hair loss occurs when hair thinning occurs at the frontal and parietal.

Causes

 * Alopecia mucinosa
 * Androgenic alopecia
 * Dissecting Cellulitis
 * Fungal Infections (such as tinea capitis)
 * Hair Treatments (chemicals in relaxers, hair straighteners)
 * Hereditary Disorder
 * Hormonal Changes
 * Hyperthyroidism and Hypothyroidism
 * Hypervitaminosis A
 * Iron deficiency
 * Lupus Erythematosus
 * Medications (side effects from drugs, such as chemotherapy)
 * Pseudopelade of Brocq
 * Radiation therapy
 * Scalp infection
 * Secondary syphilis
 * Telogen effluvium
 * Traction alopecia
 * Trichotillomania
 * Tufted folliculitis

Pathophysiology
Hair follicle growth occurs in cycles. Each cycle consists of a long growing phase (anagen), a short transitional phase (catagen) and a short resting phase (telogen). At the end of the resting phase, the hair falls out (exogen) and a new hair starts growing in the follicle beginning the cycle again.

Normally about 100 hairs reach the end of their resting phase each day and fall out. When more than 100 hairs fall out per day, clinical hair loss (telogen effluvium) may occur. A disruption of the growing phase causes abnormal loss of anagen hairs (anagen effluvium).

Diagnosis
Evaluation for causative disorders should be done based on clinical symptoms. Because they are not usually associated with an increased loss rate, male-pattern and female-pattern hair loss don’t generally require testing. If hair loss occurs in a young man with no family history, the physician should question the patient on drug and illicit drug use.
 * The pull test: this test helps to evaluate diffuse scalp hair loss. Gentle traction is exerted on a group of hair (about 40–60) on three different areas of the scalp. The number of extracted hairs is counted and examined under a microscope. Normally, <3 hairs per area should come out with each pull. If >10 hairs are obtained, the pull test is considered positive.
 * The pluck test: In this test, the individual pulls hair out “by the roots.” The root of the plucked hair is examined under a microscope to determine the phase of growth and used to diagnose a defect of telogen, anagen, or systemic disease. Telogen hairs are hairs that have tiny bulbs without sheaths at their roots. Telogen effluvium shows an increased percentage of hairs upon examination. Anagen hairs are hairs that have sheaths attached to their roots. Anagen effluvium shows a decrease in telogen-phase hairs and an increased number of broken hairs.
 * Scalp biopsy: This test is done when alopecia is present, but the diagnosis is unsure. The biopsy allows for differing between scarring and nonscarring forms. Hair samples are taken from areas of inflammation, usually around the border of the bald patch.
 * Daily Hair Counts: This is normally done when the pull test is negative. It is done by counting the number of hairs lost. The hair that should be counted are the hairs from the first morning combing or during washing. The hair is collected in a clear plastic bag for 14 days. The strands are recorded. If the hair count is >100/day, it is considered abnormal except after shampooing, where hair counts will be up to 250 and be normal.
 * Trichoscopy: Trichoscopy is a non-invasive method of hair and scalp. The test may be performed with the use of a handheld dermoscope or a video dermoscope. It allows differential diagnosis of hair loss in most cases.

Treatment

 * Minoxidil (Rogaine): This is a non-prescription medication approved for androgenetic alopecia and alopecia areata. Minoxidil comes in a liquid or foam that is rubbed into your scalp twice a day. This is the most effective method to treat male-pattern and female-pattern hair loss . However, only 30–40% of patients experience hair growth. Minoxidil is not effective for other causes of hair loss except alopecia areata. Hair regrowth can take 8 to 12 months. Treatment is continued indefinitely because if the treatment is stopped, hair loss resumes again. Most frequent side effects are mild scalp irritation, allergic contact dermatitis, and increased facial hair.
 * Finasteride (Propecia): Is used in male-pattern hair loss in a pill form taken on a daily basis. Finasteride is not indicated for women and is not recommended in pregnant women. Treatment is effective within 6 to 8 months of treatment. Side effects include decreased libido, erectile dysfunction, ejaculatory dysfunction, gynecomastia, and myopathy. Treatment should be continued as long as positive results occur. Once treatment is stopped, hair loss resumes again.
 * Corticosteroids: Injections of cortisone into the scalp can be used to treat alopecia areata. This type of treatment is repeated on a monthly basis. Physician may prescribe oral pills for extensive hair loss due to alopecia areata. Results may take up to a month to be seen.
 * Anthralin (Dritho-Scalp): Available as a cream or ointment that is applied to the scalp and washed off daily. More commonly is used to treat psoriasis. Results may take up to 12 weeks to be seen.
 * Hormonal Modulators: Oral contraceptives or spironolactone can be used for female-pattern hair loss associated with hyperandrogenemia.
 * Surgical Options: Treatment options such as follicle transplant, scalp flaps, and alopecia reduction are available. These procedures are generally chosen by those who are self-conscious about their hair loss. These options are expensive and painful. There is a risk of infection and scarring. Once surgery has occurred, it takes 6 to 8 months before the quality of new hair can be assessed.
 * Hair transplant: A dermatologist or cosmetic surgeon takes tiny plugs of skin, each which contains a few hairs, and implants the plugs into bald sections. The plugs are generally taken from the back or sides of your scalp. Several transplant sessions may be necessary.
 * Scalp Reduction: This process is the decreasing of the area of bald skin on your head. As time goes, the skin on our head becomes flexible and stretched enough that some of it can be surgically removed. After the hairless scalp is removed, the space is closed with hair-covered scalp. Scalp reduction is generally done in combination with hair transplantation to provide a natural-looking hairline, especially those with extensive hair loss.


 * Wigs: As an alternative to medical and surgical treatment, some patients wear a wig or hairpiece. They can be used permanently or temporarily to cover the hair loss. Quality, and natural looking wigs and hairpieces are available.

Research
In May 2009, researchers in Japan identified a gene, SOX21, that appears to be responsible for hair loss in humans and a researcher in India found the missing link between androgenic hormone and hair loss. Androgenic alopecia is said to be a counterproductive outcome of the anabolic effect of androgens.