While loss of head hair is a common problem, hair loss on the arms and legs is a much rarer condition. According to the site Hair Loss Expert, this manifest itself as either a complete loss, or as a significant and noticeable decrease in the amount of hair growing on the limbs. In either case, there are six main causes of arm and leg hair loss.
A number of skin conditions can cause arm and leg hair loss, including dermatitis, seborrhea, psoriasis, eczema and keratosis pilaris. Dermatitis refers to a general inflammation of the skin; both eczema and seborrhea are types of dermatitis that cause flaky red and itchy patches to develop on the skin. Psoriasis is caused by immune cells attacking healthy skin, and keratosis pilaris is an inflammatory disease of the skin hair follicles. Severe skin injuries and burns can also damage hair follicles and epithelial cells to the point that they can no longer support hair growth.
Both Hair Loss Adviser and Healthcare366.com report that steroid use, particularly the steroids that bodybuilders use that contain testosterone and other muscle-building substances, can cause widespread body hair loss on the arms and legs if taken for long periods of time. MayoClinic.com also reports body hair loss as a side effect of steroid use, though mainly for women.
Alopecia universalis, hyperthyroidism, hypothyroidism and pituitary gland disorders are all medical conditions that can cause excessive arm and leg hair loss. Alopecia universalis is linked to immune system problems, while hyperthyroidism and hypothyroidism are linked to an overproduction and underproduction of thyroid hormones, respectively.
Many prescription medications can cause arm and leg hair loss, including drugs for high blood pressure or cholesterol; drugs used to treat conditions such as Parkinson's disease and arthritis; anticoagulants; and hormone replacement therapy drugs. Chemotherapy drugs, which are known to cause hair loss on the head, can also cause limb hair loss.
Diet and Stress
Lifestyle factors, such as extreme physical, mental or emotional stress, and a diet regularly lacking certain essential vitamins, minerals and nutrients such as iron can contribute to unusual hair loss.