நடு மண்டைல மட்டும் ஏன் சொட்ட விழுது?

Male pattern baldness is a common form of hair loss in men where hair recedes at the temples and thins across the top of the scalp while remaining intact on the sides and back. This condition occurs when the hormone dihydrotestosterone causes hair follicles, the tiny pockets in the skin that produce hair, to shrink and eventually stop growing new strands.

The role of DHT

Dihydrotestosterone, or DHT, is created when the hormone testosterone is converted inside the skin and hair follicles. Production begins during the teenage years between ages 14 and 16, which promotes beard and moustache growth. In some men around age 25 or 30, testosterone converts into higher levels of DHT on the scalp. This hormone binds to hair follicles, causing them to shrink so that hair becomes progressively thinner before falling out permanently.

Progression and the Norwood Scale

• Hair loss usually begins with thinning at the temples along the front hairline.
• Thinning then develops at the crown in a circular pattern and eventually joins the receding front.
• Doctors classify the stages and patterns of this hair loss using a measurement chart called the Norwood Scale.

Why hair loss affects the crown

Under the skin across the top of the head lies a tough connective tissue called the galea, which is part of a muscle-linking tissue network known as an aponeurosis. As surrounding head and facial muscles move, they pull on the galea and create high mechanical tension across the crown of the head. This tension triggers mild, long-term inflammation in the skin directly above it. That inflammation speeds up the local conversion of testosterone into DHT, causing nearby follicles to shrink.

Why sides and back remain safe

The mechanical tension and inflammation caused by the galea are concentrated only on the top and crown of the skull. The hair follicles on the sides and back of the head do not experience this tissue pulling, so they are not damaged by high levels of DHT. In addition to scalp tension, factors such as genetics inherited from fathers or grandfathers, as well as stress, can increase the enzyme activity that turns testosterone into DHT.