Classic male-pattern hair loss begins above the temples and vertex of the scalp. As it progresses, a rim of hair at the sides and rear of the head remains. This has been referred to as a 'Hippocratic wreath', and rarely progresses to complete baldness. The Hamilton–Norwood scale has been developed to grade androgenic alopecia in males.
Androgenic Alopecia is a common genetic condition, caused by a chemical in our bodies called Dihydrotestosterone, DHT. Testosterone is converted to DHT by 5 Alpha Reductase Enzyme. DHT attaches to the androgen receptors on the hair follicle causing gradual miniaturisation of the hair follicle resulting in finer and shorter hair being produced until the follicle eventually dies and hair loss occurs.
Alopecia Areata causes patchy hair loss that can come on suddenly, causing bald patches which are often circular. This hair loss condition is often triggered by stress or extreme shock and can be temporary, appearing around three months after the initial incident which caused the distress.
Female-pattern hair loss more often causes diffuse thinning without hairline recession; similar to its male counterpart, female androgenic alopecia rarely leads to total hair loss. The Ludwig scale grades severity of female-pattern hair loss.
Telogen Effluvium occurs when sudden or severe stress causes an increase in the shedding of hair. The condition is generally temporary and hair will typically grow back within 6- 9 months.