Root Hair Institute



types of hair loss

The medical term for hair loss is alopecia. There are many different types of alopecia.

Androgenetic Alopecia

The most common type of hair loss is androgenetic alopecia which is also known as male/female pattern hair loss/baldness and is the genetic and hormonal type of hair loss. This is the type of hair loss many people think of as balding or thinning. Despite what many think, the genetic component of this type of hair loss is inherited from both sides of the family. In many cases the patterned distribution of hair loss (with a relatively preserved “horseshoe” appearance of hair from ear to ear) is in part explained by the relatively high sensitivity of follicles to dihydrotestosterone (DHT) in areas with loss versus less sensitivity of follicles to DHT in the unaffected areas. However, there are numerous other contributing factors and pathways in androgenetic alopecia beyond DHT including oxidative stress, inflammation, prostaglandins, etc. 


For more information on these other factors and pathways see our recent article in Dermatology Clinics.

Telogen Effluvium

Another type of hair loss is shedding type of hair loss, termed telogen effluvium, which occurs with any type of physical or emotional stressor on the body. Causes of shedding hair loss or telogen effluvium include things like medications, pregnancy, febrile illnesses including COVID-19, surgeries, emotional stress, and many internal conditions such as low thyroid, iron, or Vitamin D. It is important to note that often the shedding in telogen effluvium does not occur until 3-6 months after the inciting stressor.

Traction Alopecia

Traction alopecia is a type of hair loss caused by prolonged pulling or tension on the hair follicles. This is a common form of hair loss especially in those who frequently wear their hair in tight hair styles such as tight ponytails or braids. It is important that tight hairstyles be avoided in these cases to minimize ongoing damage to the hair follicle as continued trauma from the pulling can eventually lead to permanent loss.

Alopecia Areata

There is also an auto-immune type of hair loss called alopecia areata. This is often the type of patchy hair loss that people think of when they hear the term “alopecia” (even though alopecia just means hair loss!). If alopecia areata affects the entire scalp it is called alopecia totalis. If alopecia areata affects the entire scalp and facial and body hair, then it is called alopecia universalis.

Cicatricial Alopecias

There are other types of hair loss where the hair loss can lead to scarring leading to permanent loss of hair follicles and formation of firm thickened shiny scar tissue. These scarring alopecias are termed cicatricial alopecia or scarring alopecia. These include conditions such as lichen planopilaris, frontal fibrosing alopecia, central centrifugal cicatricial alopecia, folliculitis decalvans, and dissecting cellulitis of the scalp, among many others. In many of these types of alopecia, there is a component of inflammation early on with the scarring occurring later in the course of the disease. In these cases, it is important to shut down the inflammation as much and as early as possible to minimize the degree of scarring and permanent hair loss.

Other Causes and Considerations

Even infections (like syphilis or fungal infection of the hair) or cancers spreading to the scalp can present in the human body as hair loss. Additionally, hair loss can be a sign of many specific underlying internal conditions. Thus, it is important for anyone with hair loss to seek medical evaluation with a doctor experienced with hair loss so that an appropriate work up can be done and a diagnosis can be made. 


In some cases if the diagnosis or type of hair loss is not clear, a scalp biopsy may be indicated to give more information on what the hair follicles and surrounding scalp tissue look like under the microscope and to look for things like inflammation, shrinking down of the hair follicles, the percentage of hairs that are shedding, signs of infection, etc. Labwork may also be necessary to evaluate for any underlying conditions as certain types of hair loss can be associated with anything from certain medications, hormonal imbalances, low thyroid levels, low iron levels, low Vitamin D levels, auto-immune conditions, among other conditions. 


It is extremely important to see someone specializing in hair loss for evaluation to get an appropriate diagnosis and rule out any underlying conditions. This is why we have a dermatologist as part of our team to ensure that the correct diagnosis is made and the appropriate work up performed BEFORE jumping to treatment.

Why It Matters

Why does knowing what kind of hair loss you have matter? In some cases, your hair loss could be a clue to a dangerous condition such as infection, cancer, auto-immune disease, hormonal imbalance, or nutrient deficiency. It’s important for you to know this as early as possible to get treated appropriately, and your hair loss may be one of the earliest signs. In these cases, addressing the underlying issue may lead to improvement in the hair loss, avoiding unnecessary hair loss treatments.


Even in cases where there is no underlying condition, the type of hair loss also affects the type of treatment that is best. The treatment options for the various types of hair loss discussed above vary significantly. The response to certain therapies such as prescriptions, red light devices, injections, and surgery vary between the types of hair loss. For example, hair restoration surgery is not recommended in active uncontrolled cases of scarring alopecias (as the same condition could affect and cause the transplanted hairs to be lost), telogen effluvium, or alopecia areata. The types of prescription agents recommended vary greatly depending on the type of hair loss as the pathway of each type of hair loss is different and thus the treatments are also different. 


The studies performed on various treatments are specific to a certain diagnosis or type of hair loss, so any discussion of hair loss treatment should include a diagnosis so the level of evidence of any treatment option can be discussed for the specific type of hair loss at hand. Thus it is important to be seen by an expert not only in hair loss treatment but in hair loss diagnosis and work up. We understand this at Root Hair Institute, and this is why our doctors and our approach are not only focused on treatment but on first making the correct diagnosis and performing any appropriate work up.