What is hair loss? Hair loss is the appearance of thinning hair or bald patches on the scalp, eyebrows, eyelashes, or on areas of the body that previously had hair, such as the arms or legs. On average, everyone naturally loses 50-100 of their 100,000 scalp hairs per day. Abnormal hair loss is caused when hair falls out at an accelerated rate, or when over time, hairs are not replaced as quickly as they fall out (Source: AAD). Hair loss can happen to men, women, infants and children in all socioeconomic strata and geographic areas. Genetic hair loss (androgenetic alopecia) is the most common type of hair loss. Also known as male pattern baldness or female pattern baldness, it affects around 80 million people in the United States, according to the American Academy of Dermatology (Source: AAD). Hair loss can gradually build over weeks or months, or it can occur abruptly, such as when it occurs with telogen effluvium (sudden hair loss due to a stressful physical event). Hair loss can also be due to other hair disorders, such as alopecia areata, an autoimmune disease in which the body attacks its own hair, or trichotillomania, a psychological disorder in which people pull out their own hair. Hair loss can also be a symptom of an underlying disease, disorder or condition such as anemia, thyroid disease, or lupus. Other underlying causes of hair loss may be more benign, such as use of certain harsh shampoos or hair colorants, or a nutritional insufficiency that can be easily corrected. Hair is a significant component of personal appearance in our society. As such, hair loss can deeply affect your self-image and self-esteem. There are several different types of treatments for hair loss ranging from lifestyle changes to medications and surgery, and more are being researched every day. Fortunately in many cases, lost hair can be replaced with new hair growth with treatment or on its own in time. Some causes of hair loss, such diabetes, can lead to life-threatening complications and can be fatal if they are undetected and untreated. Seeking regular medical care offers the best chances of discovering underlying diseases at their earliest, most curable stages. Seek prompt medical care if your hair loss is unexplained, is persistent, or causes you concern.