The most dominant cause of male hair loss is androgenetic alopecia, a genetic condition in which hair follicles shrink and eventually close because of the male hormone dihydrotestosterone, according to Bernstein Medical. This particular condition, also called male pattern baldness, impacts the top, front and crown.
Certain medical conditions, such as thyroid problems, alopecia areata, scalp infections and various skin disorders, also cause hair loss, reports Mayo Clinic. Drugs used to treat cancer, arthritis, depression and certain heart conditions also lead to hair loss. Mayo Clinic also notes that some people suffer thinning hair after a traumatic experience. Impulsive hair-pulling is a mental health condition in which people pull out their own hair.