Hair loss can occur anywhere on the body and as a result of many different underlying factors, including genetics, hormonal shifts, disease, medical treatments and stress, but the most common type of hair loss among both men and women is androgenetic hair loss occurring on the scalp and sometimes referred to in men as “male pattern baldness.” 
About 35 million men and 21 million women have some form of androgenetic hair loss, also called androgenetic alopecia.  In men, this type of hair loss begins at the temples and moves slowly backward, usually along the sides with concomitant thinning at the top of the head, or crown. Eventually, many men experience partial or complete baldness. In women, androgenetic hair loss typically occurs during menopause and causes hair thinning all over the head without the hairline recession typical in men. Although the hair can become very sparse, most women do not experience complete baldness as a result of androgenetic hair loss.
In men, androgenetic alopecia has been linked with an increased risk for coronary heart disease (CAD), high blood pressure, diabetes, obesity, prostate enlargement and prostate cancer. In women, it’s been associated with an increased risk of polycystic ovary syndrome, or PCOS, which causes hormonal imbalances, irregular periods, weight gain, acne and excessive growth of hair on the body. 
WHAT ARE THE SYMPTOMS?
Hair loss can occur as frank baldness or localized or disperse thinning on the scalp, face or any other area of hair growth on the body. In addition, research has shown hair loss can have a significant emotional impact affecting a person’s overall quality of life, body image, and senses of self-confidence and self-esteem. People with hair loss frequently experience depression and are less willing to socialize and less likely to enjoy social interactions.   Specific symptoms of hair loss can depend on the underlying cause of the loss and may include :
- Gradual thinning
- Circular bald spots or bald spots that occur in patches (common in alopecia areata)
- Sudden hair loosening and loss (typical of some medicines, diseases and stress reactions)
- Hair loss across the entire body
- Small, round, scaly patches on the scalp, indicative of ringworm
The type of treatment depends on the underlying cause of hair loss. Most treatments begin with topical medications such as minoxidil for both men and women or finasteride, which is used only in men. Estrogen supplementation may be helpful for women whose hair loss is related to hormonal changes. Corticosteroid ointments or injections may help promote regrowth of hair in some types of hair loss. When hair loss occurs as a result of an underlying condition like thyroid disease, the first step will be to treat that cause to see if that results in regrowth of hair.
When topical, oral or injectable medications don’t work, hair transplant surgery can be considered. However, hair transplant surgery is not successful in all types of baldness, and in cases where hair loss is complete, there may not be suitable donor follicles to complete a successful surgery.