Hair loss is a very common concern–and it’s not even an exaggeration to say that many of us will deal with hair loss or hair thinning hair at some point in our lives. For some, hair loss is a “natural” phenomenon, almost something to be expected: they’ve seen older relatives deal with it, and they expect they’ll have to deal with it too when the time comes. For others, hair loss comes as a major surprise: they’ll start noticing hair loss during or after a period of stress, after pregnancy, or even during a change of seasons. There are multiple types of hair loss, and it’s important to understand them–first, so you know what you’re dealing with, and second, so you know how to correct it (if you choose to!)
On this post:
- Types of hair loss, by cause
- Risk factors for hair loss
- Is hair loss reversible? Temporary vs permanent hair loss
- How do you choose hair growth products? Reactive vs progressive hair loss
- Can you prevent hair loss?
Types of hair loss
There are different types of hair loss, and these types are usually associated with different causes. Let’s take a deeper look at some of the more common ones:
Androgenetic alopecia
Androgenetic alopecia is the most common form of hair loss, affecting both men and women. Studies suggest “[it] has a clear genetic predisposition and is likely due to an excessive response to androgen.” Androgens, for the less scientifically inclined, are hormones that play a role in reproductive health and development–and that’s true for all humans, regardless of gender! Even if you think you’ve never heard of androgens, you’ve probably heard of one: testosterone.
In short: androgenetic alopecia is a form of hair loss influenced by both genetic and hormonal factors. It manifests as progressive hair loss that follows a different pattern in men and women. In men, this form of hair loss tends to follow a recognizable pattern, starting out at the temples and crown–this is called “male pattern hair loss”.
In women, the pattern isn’t quite as well-defined. Hair loss is more evenly distributed around the head, although it tends to be more noticeable in the crown. Often, this results in a wide hair part, where the scalp is clearly visible between the hairs. This is called “female pattern hair loss”.
Androgenetic alopecia tends to progress slowly, but it does progress. Scientically speaking, “in both males and females, it is not known how far pattern baldness will progress.” This is relevant for anyone looking for an effective treatment: according to a paper published in the Journal of Cosmetic Dermatology, “most treatments will only partially improve the condition and perhaps slow its progression.”
Alopecia areata
Alopecia areata is an autoimmune condition that consists of hair loss in well-circumscribed patches of skin. The hair loss can occur in small, round patches on the scalp, but it can also affect other areas of the body with hair, such as the eyebrows, eyelashes, and beard.
In more scientific terms, “alopecia areata is a disorder of hair follicle-cycling, where inflammatory cells attack the hair follicle [which is] then prematurely induced into the catagen phase.” The catagen phase is the part of the hair growth cycle that signals the end of active hair growth; once a strand of hair has entered the catagen phase, it stops growing.
But will it grow back? Studies suggest that “the potential for hair regrowth remains since the inflammatory process does not destroy hair follicles, especially stem cells. However, induction of regrowth by current treatments seems to be difficult to achieve.” In short: yes, hair can grow back after an episode of alopecia areata, but it’s not that simple. “Up to 34-50% of patients may recover spontaneously within one year, although most patients will experience multiple episodes of alopecia, and 14-25% of patients will progress to alopecia totalis or alopecia universalis, from which full recovery is infrequent.”
Telogen effluvium
Telogen effluvium is a temporary form of hair loss that occurs when the hair growth cycle is disrupted; in other words, it’s a reactive form of hair loss that is triggered by something going on in your life. Studies suggest that “common triggering events are acute febrile illness, severe infection, major surgery, severe trauma, postpartum hormonal changes, particularly a decrease in estrogen, hypothyroidism, discontinuing estrogen-containing medication, crash dieting, low protein intake, heavy metal ingestion, and iron deficiency.”
Did you notice that “postpartum hormonal changes” bit? Yep. A common form of telogen effluvium is the dreaded “post-partum hair loss”.
Studies suggest that “the exact prevalence of telogen effluvium is not known, but it is considered to be quite common. A large percentage of adults experience an episode of telogen effluvium at some point.” Hair loss tends to start abruptly, and can be quite frightening–those with long hair, in particular, are often alarmed by the volume of hair they can lose during one of these episodes.
The good news is that telogen effluvium is reversible, often spontaneously so: “it may take up to six months for hair growth to restart, and even longer for the growth to be appreciable by the patient.”
Traction alopecia
Traction alopecia is a form of hair loss caused by excessive tension in the hair shaft, which is, in turn, caused by a continuous pulling force on the hair roots. Traction alopecia is associated with wearing tight hairstyles like ponytails, braids or even extensions.
According to the American Academy of Dermatology Association, the first signs of traction alopecia are often broken hairs around the forehead, a receding hairline, and/or patches of hair loss in areas where the hair is under greater tension.
As far as evolution and treatment go, traction alopecia can be reversible in its early stages. However, studies suggest the condition may evolve into an irreversible form of hair loss.
Other types of hair loss
In addition to the types of hair loss we’ve listed above, there are a few others you can come across, namely:
- Trichotillomania, a psychological condition characterized by an urge to pull out one’s own hair, leading to hair loss;
- Anagen effluvium, a form of alopecia often associated with chemotherapy;
- Tinea capitis, also known as ringworm, a fungal infection that causes hair loss in circular patches.
Risk factors for hair loss
Now that you know some of the most common forms of hair loss, you realize that there are different risk factors and triggers at play in each one. While it’s hard to always pinpoint exactly what caused your specific episode of hair loss, it can be helpful to know what the “options” are:
- Genetics: family history plays a significant role in some forms of hair loss, especially androgenetic alopecia. If members of your family have experienced hair loss, it’s likely you’ll encounter the same issue too;
- Hormonal imbalances: changes in hormone levels, such as those that happen during pregnancy, childbirth, or menopause, can lead to hair loss;
- Aging: the hair tends to grow thinner and weaker as we age. In some cases, this can lead to gradual hair loss;
- Illnesses and medical conditions: autoimmune conditions and scalp infections, among others, can cause hair loss;
- Medications: some medications can cause hair loss as a side effect. Examples include chemotherapy drugs, anticoagulants, antidepressants, and some birth control pills;
- Nutritional deficiencies: a lack of essential nutrients in the diet can lead to hair thinning and shedding;
- Stress: physical or emotional stress can disrupt the hair growth cycle and result in telogen effluvium, a temporary form of hair loss;
- Hairstyles and hair treatments: tight hairstyles can cause traction alopecia, as we’ve seen. Additionally, excessive chemical treatments and heat styling can damage the hair and cause breakage (which may, in turn, look like hair thinning).
Is hair loss reversible? Temporary vs permanent hair loss
We’ve talked here about different types of hair loss based on their causes, but it’s also important to discuss them in terms of their permanence. There’s temporary hair loss, and then there’s permanent hair loss.
Temporary hair loss happens when the hair growth cycle is disturbed or affected in some way, but the hair follicle hasn’t been destroyed; Theoretically, the right treatments can reverse hair loss and restore a healthy hair growth cycle. This is called noncicatricial, or nonscarring alopecia.
Permanent hair loss happens when the hair follicles are irreversibly destroyed and no longer respond to treatment. This is called cicatricial, or scarring alopecia.
We don’t recommend that you try to understand which type applies to you based on information you can find online; as always, the best course of action is to consult your doctor.
How do you choose hair growth products? Reactive vs progressive hair loss
The distinction between “reactive” and “progressive” hair loss is particularly relevant for those who want to buy over the counter anti-hair loss products. Brands that specialize in hair loss products tend to offer two versions of the “same” product: one aimed at “reactive” hair loss, and the other at “progressive” hair loss. But what does that mean?
We’ve written about the difference between reactive and progressive hair loss in the past, but this is the gist of it: reactive hair loss is a short-term form of hair loss that occurs after a trigger (say, stress, illness, pregnancy, etc.), while progressive hair loss is a long-lasting form of hair loss that occurs without a defined onset.
Can you prevent hair loss?
While it may not always be possible to prevent hair loss–genetics play a big factor here, as we’ve seen–, there are some lifestyle changes you can try in order to minimize it. Here are some tips for preventing hair loss:
- Maintain a healthy diet, rich in essential nutrients for hair health. Foods high in vitamins (A, C, D, E), minerals (iron, zinc), proteins, and omega-3 fatty acids are all good options. You may also supplement your diet with hair supplements, but, as always, make sure to check with your doctor if they’re right for you;
- Avoid aggressive hairstyles and hair treatments. Keep tight ponytails and braids to a minimum, avoid chemical treatments (make sure to care for your hair if you do get them), and reduce heat styling;
- Focus on scalp health. Wash your hair with lukewarm water, avoid products that will sensitize or damage your scalp, and see a doctor if you spot anything out of the ordinary;
- Seek professional advice if you find yourself worrying about hair loss. Hair loss can’t always be prevented, nor can it always be treated, but this is something only a doctor will be able to tell you, once they’ve examined your hair and scalp. If you think you may be experiencing hair loss, see a doctor!
After this deep dive into the many types and causes of hair loss, we hope you feel a little more informed about this very common hair concern. As always, we recommend that you see a doctor if you find yourself a little disoriented in the fight against hair loss. There are plenty of hair loss treatments out there, and a doctor will help you spot the right one for you. Good luck!
