Baldness Cause 

The incidence of pattern baldness varies from population to population based on genetic background. Environmental factors do not seem to affect this type of baldness greatly. 1 large scale study in Maryborough, Victoria, Australia showed the prevalence of mid-frontal hair loss increases with age & affects 73.5% of men & 57% of woman aged 80 & over. According to Medem Medical Library's website, male pattern baldness affects roughly 40 million men in the United States. Approximately 25 percent of men begin balding by age 20 two-thirds begin balding by age 60. There is a 4 in 7 chance of getting the baldness gene.

Male pattern is characterized by hair receding from the lateral sides of the forehead, known as a 'receding hairline'. Receding hairlines are usually seen in males above the ages of 20 but could be seen as early as late teens as well.

An additional bald patch might develop on top . The trigger for this type of baldness is DHT, a powerful sex hormone, body, & facial hair growth promoter that could adversely affect the prostate as well as the hair located on the head.

The mechanism by which DHT accomplishes this is not yet fully understood. In genetically-prone scalps, DHT initiates a process of follicular miniaturization. Through the process of follicular miniaturization, hair shaft width is progressively decreased until scalp hair resembles fragile vellus hair or 'peach fuzz' or else becomes non-existent. Onset of hair loss sometimes begins as early as end of puberty, & is mostly genetically determined. Male pattern baldness is classified on the Hamilton-Norwood scale I-VII.

It was previously believed that baldness was inherited from the maternal grandfather. While there is some basis for this belief, both parents contribute to their offspring's likelihood of hair loss. Most likely, inheritance is technically 'autosomal dominant with mixed penetrance'.

There are several other kinds of baldness -

• Traction alopecia is most commonly found in people with ponytails or cornrows who pull on their hair with excessive force.
• Trichotillomania is the loss of hair caused by compulsive pulling & bending of the hairs. It tends to occur more in children than in adults. In this condition the hairs are not absent from the scalp but are broken. Where they break near the scalp they cause typical, short, 'exclamation mark' hairs.
• Traumas such as chemotherapy, childbirth, major surgery, poisoning, & severe stress might cause a hair loss condition known as telogen effluvium. Hair follicles in the growing phase are affected by chemotherapy while this treatment targets dividing cancer cells. Therefore, almost 90% of hairs fall out soon after chemotherapy starts.
• Worrisome hair loss often follows childbirth without causing actual baldness. In this situation, the hair is actually thicker during pregnancy due to increased circulating oestrogens. After the baby is born, the oestrogen levels fall back to normal pre-pregnancy levels & the additional hair foliage drops out. A similar situation occurs in women taking the fertility-stimulating drug clomiphene.
• Iron deficiency is a common cause of thinning of the hair, though frank baldness is not usually seen.
• Radiation to the scalp, as happens when radiotherapy is applied to the head for the treatment of certain cancers there, could cause baldness of the irradiated areas.
• Some treatments used to cure mycotic infections could cause massive hair loss.
• Alopecia areata is an autoimmune disorder also known as 'spot baldness' that could result in hair loss ranging from just 1 location to every hair on the entire body .
• Localized or diffuse hair loss might also occur in cicatricial alopecia . Tumours & skin outgrowths also induce localized baldness .
• Hypothyroidism could cause hair loss, typically frontal, & is particularly associated with thinning of the outer third of the eyebrows
• Hyperthyroidism could also cause hair loss, which is parietal rather than frontal.
• Temporary loss of hair could occur in areas where sebaceous cysts are present for considerable duration normally 1 to several weeks in length.
• Congenital triangular alopecia – It is a triangular, or oval in some cases, shaped patch of hair loss in the temple area of the scalp that occurs mostly in young children. The affected area mainly contains vellus hair follicles or no hair follicles at all, but it does not expand. Its causes are unknown & although it is a permanent condition, it does not have any other effect on the affected individuals.