TY - CHAP M1 - Book, Section TI - Androgenetic Alopecia A1 - Blume-Peytavi, Ulrike A1 - Kanti, Varvara A2 - Kang, Sewon A2 - Amagai, Masayuki A2 - Bruckner, Anna L. A2 - Enk, Alexander H. A2 - Margolis, David J. A2 - McMichael, Amy J. A2 - Orringer, Jeffrey S. PY - 2019 T2 - Fitzpatrick's Dermatology, 9e AB - AT-A-GLANCEAndrogenetic alopecia (AGA) is a nonscarring progressive miniaturization of the hair follicle in genetically predisposed men and women, usually in a specific pattern distribution.AGA onset may be at any age following puberty, showing an increasing frequency with age.The etiology of AGA is multifactorial and polygenic with, as of this writing, 12 genetic regions recognized to associate with AGA in men. In men, AGA is an androgen-dependent trait. Even though the role of androgens in female AGA is less certain than in men, there is a subset of women with AGA and associated hormonal dysregulation.Generally, diagnosis of AGA is based on history and clinical examination. Depending on patient history and clinical evaluation, however, additional diagnostics may become necessary to exclude differential diagnoses; for example, ferritin level or thyroid-stimulating hormone in diffuse effluvium or endocrinologic workup in women with signs of hyperandrogenism.Biopsy is very rarely indicated in AGA. Biopsy is indicated only if, for example, the differential diagnoses cicatricial alopecia or diffuse alopecia areata are suspected.AGA has a naturally progressive course, meaning that the main therapeutic aim is the prevention of disease progression or enhancement of hair growth during the early, mild to moderate stages of the disease.The best clinical evidence according to current study data exists for topical application of minoxidil in both genders and for the oral intake of finasteride in men. Alternatively, cosmetically satisfactory results can be achieved using hair transplantation in nonprogressive stable AGA with sufficient available donor area. SN - PB - McGraw-Hill Education CY - New York, NY Y2 - 2024/03/28 UR - dermatology.mhmedical.com/content.aspx?aid=1161325913 ER -