That common cause of hair loss -androgenetic alopecia

#dermatologyteaching
Back to dermatologist mode. Enough of Dr. Love🤷‍♀️
Let’s talk about androgenetic alopecia (AGA) aka pattern alopecia. Before we continue, you must know that alopecia in dermatology means hair loss. So when I see pictures saying “this woman is suffering from hair loss caused by alopecia”, I just know they have no idea what they’re saying. Alopecia is now divided into two types – Non scarring also called non cicatricial which means the hair follicle is not damaged or replaced by scar tissue.

Scarring/Cicatricial alopecia which means the hair follicle is damaged and replaced by scar tissue with permanent damage. It is obvious that scarring alopecia has a worse outcome than non scarring. Some hair loss may start out as non scarring and end up as scarring e.g tractional alopecia that occurs when you keep pulling your front hair in a bid to get everything in that braid 🤷‍♀️. Leave your front hair, you’ll not hear.

The topic of today is androgenetic alopecia which causes non scarring alopecia. From the name, it is easy to define it. A genetically predisposed form of hair loss that occurs due to the effect of androgen leading to replacement of the terminal hairs of the scalp with vellus hairs (a process called miniaturization of the hair follicle)

There are three types of hairs. Lanugo hair – which is found in babies (that straight silky hair that you see and you’re awwing over) that falls off shortly before birth or after birth. If an adult suddenly starts to develop lanugo hair, you need to screen for some certain types of cancer (as a paraneoplastic syndrome)

Vellus hairs – These are the fine lightly pigmented hair found on most areas of the skin.
Terminal hair – these are the thick coarse pigmented hairs found on the beard, scalp, armpits and groin.
In AGA, the terminal hairs on the scalp is gradually replaced by vellus hairs (miniaturization) and may finally fall off.

It tends to run in families and is so common that it can be seen in up to 50% of people (Male and female). Androgens are male hormones but females have them too albeit in smaller amounts. Usually will start before age 40 (most times even before 30).

Occurs more frequently in post menopausal women (in the women that it occurs in) as the effect of androgens are more pronounced then. Nobody knows why exactly it happens but genetic predisposition (both maternal and paternal genes) is the most important factor. Boys with men in their families that are bald have up to 5 times a higher chance of developing it (Screening criteria for picking husband 😂😋)

It has also been linked to increased risk of prostate hypertrophy in some studies and even cardiovascular events (refuted by some studies). Said to be the clinical equivalent of PCOS in men. The clinical significance in women has not been documented yet.

It is called pattern baldness because of the way it presents in men and women. Divided into male and female pattern baldness. In men, the hair loss starts from the sides and front and goes inwards with the centre involved later. In women, it starts from the center, and usually spares the front and sides of the scalp hair (but even when the sides are involved, it is not as obvious as seen in men).
It is not exactly understood why some progress faster than others.

The two drugs approved for treatment are Minoxidil 2% or 5% solution (the latter seems to work better) and Finasteride tablet which is an anti androgen drug. Minoxidil is pretty expensive and most of the hair may fall off when it is stopped🤷‍♀️. It is better started in the early stage. Do not go and take anti androgens like Finasteride without seeing a doctor. It will not end well o.

There are other treatment modalities like growth factors, latanoprost solution with varying responses. Surgery such as hair transplant (not readily available here) is also a choice. I reviewed a paper recently where scalp tattooing (with a black ink) to give some semblance of hair on the scalp was used. It was actually good. Again….men are also using wigs now with frontal 😁

Or you can decide to do a “who’s their daddy?” and let nature take its course (which is what most people do). Luckily, most balding men usually have full beards.
Olohun o ki n se nkan, ko ma f’aye ope le😁😁
For my students and residents, the closest differential of androgenetic alopecia especially in the early stage is alopecia areata and telogen effluvium. But once it has progressed, the clinical diagnosis is spot on.

Any questions you have will be answered on the thread or here on the website. Not DM. Thank you for reading!

Any comments, questions or clarifications?