An Introduction To Hair Loss

You may have heard the term “alopecia.” Many of my patients believe that alopecia refers to a specific type of hair loss, namely the autoimmune type of hair loss known as Alopecia Areata. In reality, alopecia simply meaning hair loss, divides into different subtypes with various causes and treatment algorithms. If your hair is thinning, you have alopecia. Let’s break it down.

TYPES OF ALOPECIA (HAIR LOSS)

SCARRING AND NON-SCARRING HAIR LOSS

If you are dealing with hair loss, it’s important to understand that there are two broad categories of alopecia: scarring and non-scarring. Inflammation of the hair follicle causes scarring alopecia (aka cicatricial alopecia), resulting in permanent hair loss. Once that follicle is gone, it’s gone for good. There is also a “point of no return” in non-scarring alopecia but, if treated early, these follicles can often be rescued.

In this blog post, we’ll focus on non-scarring alopecia. Refer to my other blog post for more information on scarring alopecia. Non-scarring alopecias include androgenetic alopecia (i.e. male- and female-pattern hair loss), telogen effluvium, alopecia areata, trichotillomania, and a few more rare sub-types. Let’s talk about these subtypes and I’ll give you an algorithm that will help you to identify which type of hair loss you have.

ANDROGENETIC ALOPECIA (MALE/FEMALE PATTERN HAIR LOSS)

Androgenetic alopecia (AGA) is colloquially known as “pattern” hair loss-i.e. male-pattern hair loss (MPHL) and female-pattern hair loss (FPHL). This is by far the most common type of hair loss. While more common in men than women, it is quite common in both. AGA occurs in at least 80% of men and around 50% of women by age 70. It often runs in families and is hormonally-mediated. In male-pattern hair loss, the front of the hairline recedes and the hair on the crown of the scalp gets thin. Female-pattern hair loss typically starts as thinning in the center of the scalp (the crown) and expands from there.

Treatment options for AGA include Minoxidil (this is generic Rogaine), Spironolactone, Finasteride/Dutasteride, low-level laser therapy, platelet-rich plasma injections, and hair transplantation.

Minoxidil

Minoxidil is a highly effective and easy-to-use medication for AGA and should be part of nearly every AGA sufferer’s regimen. It works by terminating the shedding phase early and lengthening the growing phase. It also increases the thickness of hair shafts. I like to explain its mechanism by telling patients that Minoxidil promotes the transition of hairs from the shedding phase to the growth phase by pushing out the old, stagnant hairs and bringing in thicker-caliber hairs. Because of this, Minoxidil can sometimes cause increased shedding and thinning at first. This can be disconcerting for patients, but it is really a good sign and means that it is doing its job.

Minoxidil Treatment & Side Effects

Minoxidil comes as a solution or a foam. They both work, so this is totally up to your preference. I recommend 5% for both men and women. Some women’s minoxidil is 2% and is recommended for twice-daily use. 5% has been shown to be equally effective and safe and only has to be used once daily. Side effects are minimal with minoxidil. It can cause irritation on the scalp but this is typically short-lived and resolves within a few weeks.

Minoxidil can also lead to the growth of unwanted hair on areas near the scalp, such as the forehead and ears, so make sure you are careful to apply it only to areas where you want hair to grow. Systemic side effects like headaches and leg swelling are rare. We are starting to use oral minoxidil in dermatology and this will likely be a very important part of our armamentarium in the future.

Timeline Of Minoxidil Treatment

It is important for me to note here that AGA (and hair loss in general) requires patience (like a lot of patience) and proper expectations. Ideally, we will get all the hair back but, in most cases, that is not realistic. Oftentimes I’ll call it a win if we can simply halt the progression of the hair loss. I’ve heard a rumor that if you use Minoxidil and then stop, your hair will be thinner than before you started.

Fortunately, this is not true, or at least not because of the Minoxidil (it would be because your hair loss would have progressed over that period of time anyway). Because of these expectations, I recommend that my patients plan on using Minoxidil indefinitely. I certainly plan on using mine for the rest of my life. After all, my hair loss isn’t going to give up on me any time soon so it’s just something I’ll have to continue to treat.

TELOGEN EFFLUVIUM Hair loss

Telogen effluvium (TE)-TE is an interesting type of hair loss that appears to be caused primarily by major stressors to the body. This can include both emotional and physical stressors, such as a major illness, hospitalization, surgery, pregnancy and postpartum, eating disorders and crash diets, hypothyroidism, etc. Telogen refers to the stage of the hair during TE and it is important to understand the hair cycle to understand this type of hair loss, so let’s talk about that briefly.

Hair Cycle & Hair Loss

The average scalp has about 100,000 hair follicles. Approximately 90% of these will be in the anagen phase and 10% in the telogen phase at any given time. The anagen phase refers to the growth phase, which typically lasts for years. The longer the growth phase, the longer the hair will grow. If given enough time without a haircut, one person’s hair might grow past their waist, while another’s might stop at their mid-back. This is due to the different durations of those individuals’ anagen phase.

The telogen phase is the resting/shedding stage. The normal rate of shedding is 50-200 hairs per day. In TE, the physiologic stressors I mentioned above trigger a premature transition from anagen to the telogen phase, such that a greater percentage of the hairs are in the resting phase and the rate of shedding increases proportionally. This shedding occurs over the entire scalp, not in a pattern like a male- and female-pattern hair loss. 

Timeline Of Stress Induced Hair Loss

It is important to note that the shedding and hair thinning tend to occur around months after the stressor. This is because it takes 3 months for hairs to graduate from the telogen phase and shed. When I suspect TE, I do a hair pull test to see how much shedding is going on at the moment and how many of those hairs are in the telogen phase. This increased shedding occurs over the entire scalp rather than just the crown-like in AGA. You can perform a similar test at home by combing your hair for 60 seconds over a cloth or countertop of contrasting color before shampooing. The mean number of hairs shed in patients without TE is 10. In TE, this number may be much higher, often over 100.

The prognosis for TE is quite good. Most importantly, for most people this is a self-limited problem, meaning it resolves on its own with time.