Androgenetic Alopecia or Pattern Hair Loss

What is pattern hair loss?

Pattern hair loss (androgenetic alopecia) is the leading cause of thinning hair in men and in women. It is a gradual, progressive process in which hair follicles shrink and produce finer, shorter and less pigmented hairs over time. It is often called male pattern baldness in men and female pattern hair loss in women.

Who gets it?

In men and women alike, pattern hair loss is the leading type of hair loss, and the chance of having it rises with age. In men it can start at any age after puberty, and up to half of white men have some degree of it by the age of 50. In women it most often starts in the 50s or 60s, although it can begin in the 30s or 40s, and around 4 in 10 women show some thinning by the age of 50.

What causes it?

Pattern hair loss is caused by a combination of genetics and the effect of androgens, male-type hormones present in both men and women. In people with a genetic tendency, hair follicles on the top of the scalp are sensitive to an androgen called dihydrotestosterone (DHT). Over time, this shortens the growing phase of the hair cycle and causes the follicles to shrink.

In women, most people with pattern hair loss have normal hormone levels. However, it can sometimes be associated with conditions that raise androgen levels, such as polycystic ovary syndrome, particularly if there are also irregular periods, acne or excess facial or body hair. Low iron levels and thyroid problems can make hair thinning worse.

Is it hereditary or contagious?

Pattern hair loss is inherited and can be passed down from either or both parents. Many different genes are involved, which helps explain why the age it starts and how severe it becomes vary so much, even within families. It is not contagious.

What does it look and feel like?

In men, hair loss usually starts with a receding hairline at the temples and thinning at the crown. These areas can gradually enlarge and join, leaving a horseshoe of hair around the sides and back.

In women, the frontal hairline is usually preserved. Instead, there is gradual, diffuse thinning over the top and crown of the scalp, often first noticed as a widening parting or more scalp being visible. Complete baldness is uncommon in women.

The scalp skin looks normal, and most people have no scalp symptoms, although some notice itching. Pattern hair loss can occur alongside other causes of hair shedding, such as telogen effluvium.

The emotional impact

Although pattern hair loss is common and harmless to physical health, it can have a significant effect on self-esteem and confidence, particularly in women and younger men.

How is it diagnosed?

Pattern hair loss is diagnosed from the history and the pattern of thinning, often with dermoscopy to look at variation in hair thickness. In women, blood tests may be recommended to check iron levels, thyroid function and, where relevant, hormones. A scalp biopsy is occasionally helpful if the diagnosis is unclear.

What are the treatment options?

Dr Mounsey will confirm the diagnosis and look for other factors that can add to thinning, such as iron deficiency, thyroid problems or telogen effluvium. Treatment aims to slow hair loss and encourage regrowth. Options include minoxidil applied to the scalp or taken by mouth at low dose. Men may be offered finasteride tablets, and some women may benefit from anti-androgen tablets such as spironolactone. Treatment needs to be continued to maintain the benefit. He can also advise on platelet-rich plasma, hair transplantation and cosmetic options.

What is the outlook?

There is no cure for pattern hair loss. It is progressive but usually slow, developing over several years to decades, and it tends to progress faster when it starts at a younger age. Starting management early tends to give the best results in maintaining the hair that is present.

More information

British Association of Dermatologists patient leaflet on women: https://www.bad.org.uk/pils/hair-loss-female-pattern-androgenetic-alopecia

British Association of Dermatologists patient leaflet on men: https://www.bad.org.uk/pils/hair-loss-male-pattern-androgenetic-alopecia

This page gives general information only and is not a substitute for a consultation. Everyone's skin is different, and what is right for you will depend on your own circumstances. If you are worried about a skin problem, please book an appointment with Dr Mounsey or speak to your GP. If you have a mole or skin lesion that is changing, bleeding or growing quickly, please seek medical advice promptly.