Hair loss manifests itself in a different way between men and women. Women generally experience an overall thinning to begin with before degenerating to baldness on the top of the head. The majority of thinning hair for women is due to 'female pattern baldness'. Only around 5% of hair loss cases in women is due to other causes.
Female pattern hair loss
Between 90-95% of female hair loss is due to the same reasons as men: excess DHT which leads to shorter, more brittle hairs and eventual miniaturisation and hair follicle death. Most women's oestrogen and progesterone levels protect the hair against the deleterious effects of DHT, but when women experience fluctuating levels of their female hormones, for example during menopause or pregnancy, that protection is lost and they can experience a greater shedding of hair than normal.
When hair loss occurs in a patchy manner, most commonly seen on the scalp (although it can occur anywhere on the body), the likely cause is Alopecia Areata. The hair starts to fall out with resultant smooth, circular patches which can be around the size of a coin or larger. Alopecia Areata is caused by the body's own immune system attacking the hair follicles. It can occur at any time of life and can come and go without any warning.
This type of hair loss is generally due to anaemia (low iron levels), inadequate protein, thyroid issues, surgery or illness. These causes can trigger sudden and great loss of hair. It is initially noticed when brushing the hair - large clumps will be found in the hair brush. When the cause is treated, Telogen Effluvium can often be successfully reversed - often without treatment.
Generally due to excessive pulling of the hair - frequently seen in women who braid their hair tightly against the scalp. This continuous stress can cause permanent scarring of the hair follicles and this damage will mean that the hair ceases to grow.