It is estimated that 30 million men and 20 million women in the United States suffer from hair loss each year. Many people believe that hair loss is triggered by an abrupt cessation of hair growth, but this is not the case. In actuality, it is the result of progress in the shrinking of some follicles: As this process continues, hairs will grow progressively shorter and thinner until they stop growing altogether. In the majority of cases, this decrease is due to inherited factors. Under normal circumstances, normal genes and androgens lead to progressive shrinkage of some scalp follicles over time. In men, hair loss, which may include genetic baldness, begins above the forehead and is accompanied by hair loss on the top of the head. If the doctor believes the patient’s test results warrant it, he or she may request additional blood testing to check thyroid function or testosterone levels. While alopecia areata is most commonly caused by a noncancerous and noninflammatory condition, in very rare circumstances where the alopecia appears to be caused by scarring or lumps, a pathologist may be needed to properly diagnose the issue.