GLOSSARY
GLOSSARY OF ANATOMICAL TERMS
GLOSSARY OF HAIR TYPES
GLOSSARY OF HAIR LIFE CYCLE
Alopecia Areata is thought to be an auto-immune disease of the hair, initially appearing as a rounded bare patch about an inch across. Alopecia Areata affects both men and women equally and is often experienced first in childhood. According to a survey taken in America one person in every hundred is likely to experience Alopecia Areata at some time in their life. Many people affected with Alopecia Areata will only have one experience of hair loss with re-growth occurring afterwards, however it is estimated that in approximately 20% of cases in the UK hair loss recurs or becomes permanent. There are three types of Alopecia Areata which are named according to their severity.
Alopecia Totalis is the loss of all scalp hair.
Alopecia Universalis is the loss of scalp and all body hair
In women Androgenetic Alopecia appears as diffuse hair loss occurring over most of the scalp. In men however the pattern of loss usually starts with a receding hairline which then advances to thin the top of the head.
Causes of Androgenetic Alopecia In the 1940s Dr James Hamilton concluded that genetic predisposition in the present of the male hormone androgen where the factors that caused the development of Androgenetic Alopecia.
Polygenic heredity is assumed to be the primary cause, although the male hormone testosterone plays an important role, seemingly independent of genetic predisposition. In the hair follicle cells, testosterone converts into the biologically more active metabolite, dihydrotestosterone (DHT) catalyzed by the enzyme 5-alpha reductase.
This hormone binds to androgenic receptors in the hair follicle and the specific bond triggers cellular processes which reduce the anagen phase of the hair cycle. For this reason the hair passes earlier into the telogen phase and falls out. Gradually, over 14 succeeding cycles terminal hair converts into thinner and shorter vellus hair (i.e. the retrograde phase of the cycle) and the hair follicle becomes minute.
The density of the androgenic receptors in the hair follicles varies according to location and this is genetically determined. Age factors too play an important role in AGA, the first manifestation is usually appearing in the third decade.
Androgenetic alopecia in women is less frequent. The etiology is in principle the same as in men. However, it is always necessary to exclude the possibility of endocrine dysfunction. Conversion of dehydroepiandrosterone (DHEA) into testosterone and the lack of aromatase which contributes to the conversion of androgens into estrogens are more often seen in females than in males. Apart from androgens, reduced levels of estrogens may also contribute to the incidence of AGA (hypoestrogenous AGA in women after menopause or after ovariectomy). The same may be said concerning higher levels of prolactin. Adrenal or ovarian tumors producing androgens may be a further cause.
In women with AGA the hair boundary line above the forehead is maintained, but frontally and parietally hairs are thin. The density of hair remains the same in the occipital and parietal areas Exceptionally, a retraction of the fronto-parietal hair line or the formation of a bald spot (as in men) may occur after the menopause. Clinical evaluation of AGA in women uses a three-level classification according to Ludwig.
Anagen Effluvium is the sudden hair loss which occurs as a result of chemicals or radiation, such as the hair loss that results during certain types of Chemotherapy or Radiation Treatment. In Anagen Effluvium the hair does not enter a resting stage as is does with Telogen Effluvium. The hair loss is usually sudden occurring 1 to 3 weeks after expose to the chemicals or radiation has occurred. Cancer treatments such as Chemotherapy and Radiation Treatments are the most common causes of Anagen Effluvium. However exposure to toxic chemicals such as Thallium and Arsenic may also produce a sudden loss of hair.
Chemotherapy is used in the treatment of cancer to destroy the cancer cells which divide rapidly within the body. One side effect of this cancer treatment however is that it can also stop the growth of the hair and may cause the shedding of hair. In some cases up to 90% of the hair may be affected and often the remaining 10% was already in the resting phase before the treatment was started. Some hair follicles do not shed the hair but produce a narrower weaker hair which breaks off easily. Anagen Effluvium caused by Chemotherapy is only a temporary condition and in most cases hair growth will return to normal once treatment is finished. Many people even claim that their hair grows back healthier and thicker than before. Sometimes when the hair grows back the texture can be different. Some people who have had curly hair have claimed that their hair has grown back straight and sometimes even the colour can become different. There is a wide range of drugs used in Chemotherapy and not all of these drugs cause hair loss.
Telogen Effluvium Sudden stress relate hairs loss which appears as thinning throughout the whole scalp Telogen Effluvium occurs when sudden or severe stress causes an increase in the shedding of the hair. In Telogen effluvium a sudden or stressful event can cause the hair follicles to prematurely stop growing and enter into a resting phase. The hair will then stay in the resting phase for about 3 months after which time a large amount of hair will be shed. Often the person involved will have recovered from the event before the hair loss occurs.
In most cases the hair loss is temporary and the hair soon recovers. However in some cases the hair loss continues until the underlying cause is fixed. Telogen Effluvium appears to affect more women than men because more of the precipitating event such as childbirth are experienced by women. Temporary hair loss can be caused by: Child Birth, Pregnancy Termination‟s ,Starting or Stopping Birth Control Pills, Dieting Drug Therapy, Severe Emotional Stress
Hair loss after Child Birth It is quite common for some women to experience some hair loss approximately 3 months after childbirth. This hair loss is triggered by the sudden changes in hormone levels.
Self Induced Hair loss some damage to the hair is self-inflicted sometimes consciously or unconsciously the two main types of self-induced hair loss are Trichotillomania and Traction Alopecia. Trichotillomania Trichotillomania is self-induced hair loss which results from the continuous pulling or plucking of the hair. It occurs most commonly among young children, adolescents and women and affects twice as many females as males. The hair is often pulled out in distinct patches on the scalp however some individuals also pull out eyebrows and eyelashes. The treatment for Trichotillomania often involves counselling or psychiatric help; however in some cases an antidepressant may be prescribed. Traction Alopecia Traction Alopecia is usually caused by continuous and excessive pulling on the hair due to various types of hairstyling. Ponytails, buns, braiding and cornrows often result in a continuous pulling on the hair. This traction gradually results in hair loss. If this type of traction and hair loss continues for an excessively long period of time then the hair loss may become permanent. Generally however a change in hairstyle that reduces the traction on the hair and hair follicle is all that is required in the treatment of Traction Alopecia.
Lichen Planus Lichen Planus is a rather uncommon skin disease that affects about 1% of the population. Lichen Planus is an inflammatory disease that strikes primarily the skin and mucous membranes. It usually starts as an itchy patch on the front of the wrists and forearms. The sides of the legs and ankles and lower back. In rare cases, when Lichen Planus can affect the scalp and other hairy areas this is called Lichen Planopilaris. It appears on the scalp as raised reddish-purple areas that look like lichen on a rock, or as an area of Alopecia with follicle plugging which usually clears up. Steroid lotions are used to relieve itchiness; ant malarial drugs may reduce inflammation.
Pseudopelade of Brocq Pseudopelade of Brocq is a rare Scarring Alopecia which has no potential for regrowth. It usually affects middle aged people.
Aplasia Cutis Congenita: Aplasia Cutis Congenita is a rare disorder that often results as a small blistered atrophied area usually in the midline of the scalp and present from birth. In most cases the problem heals itself however in larger areas it may be associated with underlying developmental disorders.
Congenital Atrichia : Congenital Atrichia occurs when a baby is born without hair follicles in certain areas. This can be quite common and usually only occurs in a few spots which are easy to cover.
Other types of Hair loss this section discusses a few different other types of hair loss that have not been discussed in other sections.
Syphilitic Alopecia Syphilitic Alopecia is usually a manifestation or secondary syphilis. The hair loss that occurs is patchy and often described as moth eaten. Diagnosis is made by either blood test or microscopic examination and penicillin is often used to treat the condition.
Scleroderma : Scleroderma is a disease that causes fibrosis (hardening and tightening) of the skin. The hardening is caused by excessive collagen production, which causes hardening of the skin and when it appears on the scalp interferes with the normal functioning of the hair follicles and growth of the hair. The manifestation of Scleroderma can range from mild localised Scleroderma where just a few patches may appear on the skin or it can be severe and affect the internal organs as well. This type of Scleroderma is known as Systematic Scleroderma. Scleroderma is much more common in women with the onset usually occurring between the ages of 40-60.
Tinea Capitis : Tinea Capitis is another name for ringworm, which appears on the scalp. Tinea Capitis is highly contagious and may spread throughout an entire family, school or kindergarten. It can also be passed from animals to humans as well as between people. The main symptoms or signs of Tinea Capitis is scaling and redness in a round or uneven area of stubbled hair loss. This is where the Tinea is digesting the keratin of the hair. These patches of hair loss slowly expand as the Tinea spreads.