Ludwig Scale: This is the most common classification for female pattern hair loss. There are 3 stages (ranging from mild hair loss to extensive, severe widespread thinning) and in each stage hair loss occurs on the front and top of the scalp with relative preservation of the frontal hairline. Regardless of the extent of hair loss, only women with stable hair on the back and sides of the scalp are candidates for hair transplant surgery.
Blow dryers, flat irons, and other devices: Frequent use of a blow dryer tends to damage hair. The high heat from a blow dryer can boil the water in the hair shaft leaving the hair brittle and prone to breakage. Dermatologists recommend that you allow your hair to air dry. Then style your hair when it is dry. Dermatologists also recommend limiting the use of flat irons (these straighten hair by using high heat) and curling irons.
Changing the shape, thickness and length of the eyebrow is a commonly practiced beauty technique. Some people even remove the eyebrow entirely only to replace it with a pencil-drawn mark (eyebrow pencil). As with any part of the body, repeated irritation can eventually lead to hair loss. Sometimes this is due to manual trauma, chemicals from cosmetics or even infections that arise when breaks in the skin occur. While eyebrow modification will not stop as a commonly practised beauty technique, it should at least be minimized.
Thyroid hormone receptors were detected in both dermal and epithelial compartments of the human pilosebaceous unit. T4 and T3 decrease the apoptosis of hair follicles and T4 prolongs the duration of anagen in vitro. Thyroidectomy delays initiation of anagen. Administration of thyroxine advances anagen, initiation of which is however delayed once toxic doses are given. Therefore, ratio of telogen to anagen hairs is increased in hypothyroidism as well as hyperthyroidism. Thus, the hair follicles are affected in thyroid disorders, and madarosis is caused due to disturbances in hair cell kinetics. Hypothyroidism is associated with generalized hair loss probably due to coarse, dull, and brittle hair with reduced diameter. The eyebrows and eyelashes may also be lost. Loss of lateral one-third of eyebrows known as Hertoghe sign is a characteristic sign of hypothyroidism. Some people also refer to it as Queen Anne's sign, after Anne of Denmark whose portrait with shortened eyebrows has been interpreted by some as indicative of the presence of goiter, even though such a fact has not been proved by any known sources of information. Madarosis may even be the presenting sign in hyperthyroidism. In hyperthyroidism, there is thinning with breaking off and shortening of hair. Madarosis can also occur in hypopituitarism, hypoparathyroidism, and hyperparathyroidism.