Diffuse Alopecia : This term is used when there is an excessive loss of hair from all over the scalp without producing any patch. This can be caused by a variety of conditions which can be broadly classified into three categories: (1) telogen effluvium. (2) anagen defluvium, and (3) androgenetic alopecia.
Telogen Effluvium : This is the term used when some stimulus induces a large number of hair follicles prematurely into the catagen phase which is then followed by the telogen phase. The hair loss occurs after the completion of the telogen phase and therefore it starts approximately 3 months after the onset of the causative factor(s) and when the new hairs have actually already started growing in these places. Since in most cases, the causative influence disappears by the time the hair loss starts, the patient tends to attribute the hair loss to unrelated factors. The conditions which can lead to telogen effluvium include: (1) fever due to any cause, especially if it is high. prolonged or recurrent, (2) child birth, abortion, cessation of oral contraceptives or treatment with hormones, (3) surgical operations. accidents or severe blood loss. (4) psychiatric disturbances or acute mental stress, (5) nutritional deficiencies, crash diesing or anacmia (6) hypothyroidism, hyperthyroidism or treatment with antithyroid drugs, (7) severe general illnesses, and (8) reament with anti-coagulants, anti-hypertensive drugs lithium or oral retinoids.
Diagnosis : The diagnosis of telogen effluvium can be nfirmed by examining the falling hairs. The telogen hairs have a club-like swelling at the root end and are therefore called club hairs and are shorter than the maximal hair length for that area.
Anagen Defluvium : This is the term used when the causative agent interrupts the growth of the hair in the anagen phase itself. This leads to the development of a weak spot at the growing end of the hair which then tends to break and fall off. Generally anagen defluvium is caused by antimitotic drugs such as cyclophosphamide, vinblastin, adriamycin and less frequently by other antimitotic drugs. X-ray therapy to the sealp or thallium poisoning can also lead to anagen defluvium.
Diagnosis : The hairs falling due to anagen defluvium are likely to show fractured or narrowed proximal ends while the club hairs are absent.
Androgenetic Alopecia :The common baldness seen in the males is called andro-genic or androgenetic alopecia. The term androgenetic alopecia is more appropriate than the term androgenic alopecia because the disease is based not only on the effect of androgenic hormones, but it also requires a genetic predisposition for this disease. It is transmitted as an autosomal dominant gene and thus presence of baldness in the male members of the family both on the paternal and the maternal side is common. The females manifest only minor forms of this type of baldness and never go complerely bald. Even in the males, the baldness is limited to the frontal, the temporal and the vertical areas of the scalp, while a rim of hair on the back and the sides of the scalp is never lost. The hair in the involved areas become progressively finer till these areas are completely bald. The rate of balding varies in different individuals.
Alopecia Areata : This term is used when the hair loss occurs from localized areas of the scalp or other body sites without any other change in the skin. The disease is common in children and young adults. It usually starts as a single patch located anywhere on the scalp. In some cases, the patch may appear on some other hairy areas of the body, such as the cyebrows, eyelashes, beard region, moustache or even the trunk and the extremities. In a majority of the cases, the patch persists for 3-6 months after which the hairs start regrowing spontaneously without any treatment. Such cases are believed to be caused by a stimulus which temporarily interferes with the growth of the hairs. In a smaller percentage of patients the patch of alopecia continues to increase in size, and involve other areas as well. leading to a total loss of all the hairs on the scalp (alopecia totalis), and other regions of the body (alopecia universalis). These cases are considered to be based on auto-immune phenomena and may also develop pitting of the nails.
Secondary Alopecia : Some skin diseases which involve other parts of the body may also produce lesions on the scalp and lead to localized areas of alopecia. In some of these diseases such as tinea capitis, lupus erythematosus and secondary syphilis, the alopecia is reversible after the primary disease has beer treated. In other diseases, especially morphoea and liche planus the disease process permanently destroys the hair follicles and therefore regrowth of the hairs does not occur.
Diagnosis : In each case the regional skin shows the signs and symptoms of the primary disease. For diagnosis therefore, the tests required are the same as those required for diagnosing the original disease.
Folliculitis Decalvans : This term is used when the patient develops patchy areas of cicatricial alopecia which are preceded by follicular papulo-pustules
Pseudopelade : This term is used when the cicatricial alopecia is not preceded by any type of skin lesions. Both the diseases are slowly progressive for vanabla periods. The hair loss is permanent.
Trichotillomania : Some patients develop the habit of pulling out the hairs from their scalp whenever they are tense emotionally. This leads to localized arcas of baldness. The skin is otherwise normal. In due course the hairs start regrowing in these areas, but the patient may continue to pull the hairs out from the adjoining areas. This produces a characteristic picture where the patient shows areas on the scalp with varying lenths of regrowing hairs.
Traction Alopecia:Patients who tie their hair so tight that it causes too much of traction at the hair roots can develop a progressive loss of hair in these areas. Patients who have a heavy growth of hair on their scalp and tie them into a big knot can also produce sufficient traction at the hair roots even if the knot is not too tight. This type of alopecia is particularly common in the girls who make a pony-tail, or the sikh boys or the girls who tie a big knot of their hair.
Premature Greying of Hair : This is also called canities. This term is used if a person develops grey hairs at an carly age, usually earlier than 2:5 years. This condition is transmitted in families as an autosomal dominant character.
Treatment : Oral treatment with 100 mg calcium pantothenate twice a day has been observed to reverse the process in about half the patients.
White Forelock : This term is used when an individual has a bunch of white hair growing from a localized area of the scalp. It is usually present at birth and the skinat this area is normally pigmented
Hypertrichosis : An excessive growth of coarse hairs on those areas of the body which do not normally have coarse hairs is called hypertrichosis. The term hirsutism is used when a female has coarse hairs in those areas of the body where normally only the males have coarse hairs. These areas include, the beard region, the upper lip, the central part of the chest, breasts and the areola of the nipple, and upper part of the pubic region. Hypertrichosis is rare and occurs as a manifestation of some neurocutaneous or metabolic disorders such as porphyria. Hirsutism on the other hand is very common. Severe cases are caused by an excess of androgenic hormones and are commonly seen in association with polycystic ovaries, androgen producing tumours or congenital adrenal hyperplasia. Most cases of hirsutism however are of a minor degree and not associatec with androgen excess. Diagnosis : In all cases it is necessary to investigate the patient to detect the underlying cause if any.