What is Androgenetic Alopecia?

Overview

Androgenetic alopecia (AA), or pattern hair loss, is a predetermined genetic condition that can affect assigned males at birth (AMAB) and assigned females at birth (AFAB). It is very common, as nearly 50% of AFAB and AMAB are affected. However, they are usually affected differently. Typically, AMAB have hair loss towards the front and centre of the scalp, whereas AFAB tend to notice hair loss towards the crown of the head, and it may be more diffused. This is normally noticed as hair thinning first.¹

Pathophysiology

The pathophysiology involved in androgenetic alopecia is the hair cycle, follicular miniaturisation, and inflammation, with follicular miniaturisation being the most important part. Androgenetic alopecia occurs when there is excessive activation of the androgen receptor. This shortens the growth phase in the hair cycle. When this process is prolonged, follicular miniaturisation occurs, and hair starts to become thinner and shorter and can no longer penetrate through the skin, creating the appearance of baldness.² 

Causes and risk factors

Androgenetic alopecia has a genetic component, which means that some people with certain genes are more likely to have androgenetic alopecia in their lifetime.¹ Research shows that androgenetic alopecia is polygenic, and as such, multiple genes are associated with its cause. As this disorder is genetic, if a father experiences pattern baldness, his children are up to six times more likely to have it as well.¹ 

Furthermore, a person’s ethnicity may also impact their risk of having androgenetic alopecia. The list below goes from most likely to least likely:

• White patients
• Asians
• African Americans
• Native Americans
• Eskimos¹

Notably, this type of balding can only occur after puberty. Research suggests that androgenetic alopecia also involves hormones like testosterone, metabolism, and the and rogen receptor. Additionally, assigned females at birth are more likely to notice patterned baldness after menopause.¹

Clinical presentation

Normally, androgenetic alopecia is easily recognisable. Usually, someone will notice a thinning or bald patch appearing on their scalp. Most often, these are found at the front hairline or towards the crown at the top of the head. This hair loss can start as young as the late teens to early twenties but normally starts later in life. It can also take many years for significant hair loss to be noticed.³ There are two types of patterned hair loss. 

Macroscopic hair loss 

This type is visible to the naked eye and is usually a result of genetics, age, and possibly other medical conditions. People tend to notice thinning or bald spots on their scalp.²

Microscopic hair loss

This is not always visible to the naked eye as it involves gradual miniaturisation, so hair thinning is typically noticed first. This form of hair loss can be caused by stress, hormone imbalances, malnutrition, and other medical conditions.²

Diagnosis

Androgenetic alopecia is diagnosed by a healthcare professional who will examine the scalp. If you think you may have pattern baldness, you can ask a doctor or dermatologist to confirm your diagnosis. They will be able to explain what this diagnosis means and suggest some treatment options you may want to consider.

Normally, a scalp examination is enough to diagnose androgenetic alopecia; however, further tests such as biopsies or blood tests. Biopsies are used to assess the terminal anagen hair count, i.e., the hair count at the end of the growth stage. If you have hair loss, this count will be lower than normal.⁴ 

Treatment options

Although androgenetic alopecia doesn't need treatment as a health concern, some people may want to consider some options as this type of pattern baldness can impact people’s self-esteem, confidence, and social functioning. Currently, there are only two FDA-approved drugs that are used to treat androgenetic alopecia. These are topical Minoxidil and oral Finasteride. However, there are alternative treatments such as laser treatment, hair transplants, platelet-rich plasma treatment, and herbal remedies such as using rosemary oil.³

Topical minoxidil

Topical minoxidil is available in different concentrations, usually 2% and 5%. It slows hair loss by increasing the length of the anagen phase (growth phase). This helps promote hair growth and increases density and thickness. Topical minoxidil stimulates cutaneous blood flow within 10-15 minutes. However, results start to show around 4-8 months after starting treatment and begin to stabilise after 12-18 months. Research indicates that the 5% solution is more effective than a 2% solution.⁵

This treatment should be applied directly onto the scalp using an aerosol administration. AMAB should use a 5% solution twice a day whereas AFAB should use it once a day. Furthermore, some studies suggest that microneedling following the treatment increases its efficacy.⁵

Oral finasteride

Oral finasteride is available as a 1 mg tablet. It has been shown to reduce hair loss after long-term use. This treatment may take up to five years for significant results to be seen. Although this treatment is FDA-approved and effective, there are a few negative side effects to be cautious of. One main side effect is sexual dysfunction, including erectile dysfunction and low libido.⁶

Laser treatment

Low-level laser therapy (LLLT) is administered using at-home devices and works by promoting vasodilation through red light absorption. Studies have found that this treatment significantly improves hair growth. Also, this type of treatment is very convenient and easy to use, as well as having minimal side effects in comparison to other treatments.⁶

Hair transplant

A hair transplant is a surgical procedure that involves transplanting hair follicles from a donor hair area to the area of concern. This treatment has to be carried out by a qualified surgeon and is highly successful providing permanent results, unlike other treatments that need to be maintained. Although this treatment is very effective, it is very expensive for a single treatment and there may be challenging side effects that include a long recovery period involving pain and bleeding.⁶

Platelet-rich plasma

Platelet-rich plasma is an injectable treatment for hair loss. It contains growth factors to help increase hair count and density. It's a long-term option, and is usually given in 4-8 ml injections per session. A typical treatment course involves monthly sessions for three months followed by a treatment every three months for a year. This type of treatment is not suitable for everyone as it may interfere with pre-existing medical conditions. Therefore, consulting with a professional is a must before considering this treatment.⁷

Plant-based oils 

Plant-based oils like rosemary, tea tree, and pumpkin seed are a good alternative treatment for androgenetic alopecia. Rosemary oil is one of the most common oils used for this type of treatment. The oil is applied topically to the scalp. A study comparing the effects of rosemary oil and topical minoxidil showed that after six months of regular use, both treatments had resulted in a significantly increased hair count.⁸ There are also some mild side effects associated with oil treatments. Often your hair may feel oily and greasy and require regular washing. However, this treatment is cheaper and easily accessible compared to other treatments.⁶ 

Microneedling

Microneedling is an in-practice procedure that involves a small tool with tiny needles on it. These needles gently pierce the skin to promote wound regeneration and release growth factors. This helps increase hair thickness and density. This treatment is generally safe for most people as it has few side effects and is used alongside other treatments, including topical minoxidil.⁶

Prevention and lifestyle

Although there is no certain way to prevent balding due to its genetic predisposition, there are ways to slow down or encourage healthy hair growth. A way to do this is to maintain a healthy lifestyle and reduce your stress.² Using techniques to help stimulate blood flow to the scalp and promote growth factors can also help improve hair thickness and density, like scalp massages.⁵ Furthermore, keeping your hair healthy and preventing breakage is also very important. To do this you could try using good quality shampoos and conditioners as well as hair treatments regularly.² 

Summary

Androgenic alopecia, also known as patterned hair loss, is a genetically linked condition that affects up to 50% of the population. The underlying mechanism of AA is that there is a disruption to the hair cycle by shortening of the hair growth phase. Diagnosis is made through a scalp examination; however, further testing such as biopsies and blood tests can be used.

AA is not a medical concern, and therefore it does not necessarily need treatment. However, some people may choose to consider different treatment options to improve their self-esteem and confidence. Treatment options include prescribed medications, hair transplants, injectables, laser treatments, microneedling, and plant-based oil treatments. It is best to consult a doctor or dermatologist before beginning these treatments.