Androgenetic Alopecia

Definition: Androgenic Alopecia (AGA) is one of the most common types of hair loss and is characterized by the androgen-dependent reduction of terminal hairs into thin vellus hairs (1). 

Etiology:  AGA is a hereditary disorder for which there is no known cure and is mainly influenced by androgens such as dihydrotestosterone (1). 

Epidemiology: AGA affects both men and women with different balding patterns (1,3). The prevalence differs with men being more commonly affected (3).

Signs: In women’s hair the frontal hairline is usually retained with diffuse thinning throughout the crown (2). In males, the thinning starts at the vertex and temples leading to receding in a characteristic “M” shape (2)

Symptoms: Typically asymptomatic but can have psychological impacts due to the impact on the patient’s appearance. 

Differentials: Alopecia Areata, Frontal Fibrosing Alopecia, Hereditary hypotrichosis complex, Telogen effluvium, Triangular Alopecia, Trichorhinophalangeal syndrome (1).

Diagnosis: Advanced AGA is a clinical diagnosis, however in early AGA scalp dermoscopy, pull tests, hair and scalp examinations and biopsies may be used (3). Dermoscopy will show miniaturized hair follicles. (3)

Treatment: There are only two drugs available, topical Minoxidil (men and women), a pyrimidine derivative and oral finasteride, a SRD5A2 inhibitor (for men only) (1,3).

References: (AMA)

1.     Khan Mohammad Beigi P. Alopecia areata. Published online 2018. doi:10.1007/978-3-319-72134-7

2.     Androgenetic alopecia: Medlineplus genetics. MedlinePlus. 2023. Accessed August 18, 2024. https://medlineplus.gov/genetics/condition/androgenetic-alopecia/#resources

3.      Ntshingila S, Oputu O, Arowolo AT, Khumalo NP. Androgenetic alopecia: An update. JAAD International. 2023;13:150-158. doi:10.1016/j.jdin.2023.07.005