More than 95% of hair thinning in men is male pattern hair loss (also known as androgenic alopecia). Male pattern hair loss is characterized by hair receding from the lateral sides of the forehead (known as a “receding hairline”) and/or a thinning crown (balding to the area known as the ‘vertex’’). Both become more pronounced until they eventually meet, leaving a horseshoe-shaped ring of hair around the back of the head.
The incidence of pattern for hair loss in Men varies from population to population and is based on genetic background. Environmental factors do not seem to affect this type of baldness greatly. One large scale study in Maryborough, Victoria, Australia showed the prevalence of mid-frontal baldness increases with age and affects 73.5 percent of men and 57 percent of women aged 80 and over. A rough rule of thumb is that the incidence of baldness in males corresponds to chronological age. For example, according to Medem Medical Library’s website, male pattern baldness (MPB) affects roughly 40 million men in the United States. Approximately 25 percent of men begin balding by age 30; two-thirds begin balding by age 60.
For hair loss in men there is a 4 in 7 chance of receiving the baldness gene. Onset of hair loss sometimes begins as early as the end of puberty, and is mostly genetically determined. 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.
The trigger for this type of baldness is DHT (or dihydrotestosterone), a body- and facial-hair growth promoter that can 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 (i.e., those experiencing male or female pattern baldness), DHT initiates a process of follicular miniaturization, in which the hair follicle begins to deteriorate. As a consequence, the hair’s growth phase is shortened, and young, hair is prevented from growing and maturing into the deeply rooted hair that makes up 90 percent of the hair on the head. In time, hair becomes thinner, and its overall volume is reduced so that it resembles fragile hair or “peach fuzz” until, finally, the follicle goes dormant and ceases producing hair completely.
The Norwood scale is a classification system that helps diagnose alopecia, measuring the baldness degree of the patient. For this, a graphic pattern is used to explain the progressiveness of the condition.
Level 1: Minimum hair loss.
Level 2: Small recession of the hairline, the density slowly fades.
Level 3: The recession is accentuated, the pattern starts showing in the crown.
Level 4: The baldness is accentuated with little or no hair on the top part of the head.
Level 5: The line dividing the front and crown is diminished.
Level 6: The front and the crown merge, leaving few hair spots in between.
Level 7: This is the highest degree of baldness, where there is only a strip of hair stretching from ear to ear.