This article will address one-sided hair loss. This will include a look at its most common causes, as well as the treatments you can use to combat it and regrow your hair.
What Is One-Sided Hair Loss?
One-sided hair loss is thinning and hair loss that occurs – either in part or in totality – on one side of the scalp. This may occur in discrete patches, or more diffusely over larger areas of the head. Either way, the result is an asymmetrical appearance of the hair.
While not very common, one-sided hair loss can happen for a number of reasons. Even in individuals with Androgenetic Alopecia (AGA), recession may occur more quickly on one side than the other (known as an uneven hairline). However, true one-sided alopecia is usually caused by different conditions.
What Causes This Uneven Hair Loss?
Here are a few causes of uneven hair loss.
Alopecia Areata (AA) is an autoimmune disorder that leads to patchy, nonscarring hair loss. The tell-tale sign of alopecia areata is clearly defined patches of completely bald scalp, surrounded by more or less intact hair (1). Unlike male or female pattern baldness that progresses in a predictable fashion, alopecia areata can strike at any part of the head.
The bald patches can appear anywhere on the head, and may or may not also appear on other parts of the body, like the beard, eyelashes, eyebrows, or bodily hair. Because of its random nature, alopecia areata of the scalp will almost always lead to asymmetrical hair loss.
The causes are not fully understood, but it seems almost certain that there is a strong autoimmune component (2). T cells are white blood cells that form part of the immune system and play a critical role in attacking pathogens like viruses. But for reasons that are still unknown, in alopecia areata these T cells infiltrate the hair follicles and lead to hair loss (3).
While AA is often reversible if caught early, in its chronic version it can lead to follicle miniaturization and permanent hair loss, just like with pattern baldness. Alopecia areaeta is often associated with thyroid problems and your doctor needs to do blood tests and make recommendations (4).
In addition to the patchy form of AA, which is by far the most common, there are cases with total balding of the scalp and face (alopecia totalis) as well as total body hair loss (alopecia universalis).
An impulse control disorder that leads to the pulling out of one’s own hair, trichotillomania is a common cause of patchy hair loss (5). Individuals with trichotillomania may pull hair from their scalp, their eyelashes or eyebrows, as well as other parts of the body like the arms, legs, or chest.
The impulse to pull one’s hair is purely psychological in nature, without any underlying pain or discomfort, and will often be a mystery to the patients themselves.
Sometimes the hair pulling is done unconsciously, without the patient even realizing, but other times it is the result of conscious and very focused plucking (6). The condition is more common in girls and women, though men can also be affected.
There are treatment options for individuals suffering from this disorder (including therapy and medication). If the hair pulling has gone on for an extended period of time, the hair follicles may be permanently damaged, and the hair might not grow back fully.
Trauma or Illness
From head injuries to stroke, there are a number of injuries and illnesses that can trigger asymmetrical hair loss. Scarring and poor blood flow to a particular location of the scalp are two of the common causes of injury- and illness-related hair loss. Depending on location, these can lead to asymmetrical hair loss.
Dandruff and Seborrheic Dermatitis
Dandruff is a very common condition, affecting as much as one half of the general population (7).
Though we all lose skin cells on our scalp all the time as the result of the natural cell lifecycle, in dandruff these cells retain a high degree of cohesion and fall off in large chunks. These are the white flakes that are the hallmark of the condition.
Seborrheic dermatitis is a related condition that is generally milder than dandruff and can appear in areas outside the scalp, like the face and chest (8).
Neither of these conditions lead to alopecia in and of themselves. Over time, the constant itching and inflammation associated with them can certainly lead to hair thinning and balding. If these symptoms are more prevalent on one particular area of the scalp, this could potentially lead to uneven hair thinning.
Though far rarer than the aforementioned, another possible cause of one-sided hair loss can be fungal infection, leading to patchy and seemingly random bald patches.
The most common fungal infection causing hair loss in the scalp is tinea capitis, commonly – and incorrectly – referred to as scalp ringworm (9).
Finally, a rare inflammatory condition known as lichen planus can affect the scalp in an asymmetrical pattern, leading to irreversible hair loss in the affected areas (10).
How to Treat One-Sided Hair Loss
With a better understanding of the most common causes, it is now time to learn how to treat the underlying issue so you can regrow your hair.
1. Find the Cause
As shown above, there are a few conditions or circumstances that can lead to one-sided hair loss. In order to properly treat the issue, you need to narrow down the cause. In some cases, the cause can be easy to determine. However, you may also require the help of a dermatologist.
2. Treat the Issue at Its Source
After you have identified the cause of the one-sided hair loss, the next step is to take the appropriate action.
The most effective treatment for trichotillomania is behavioral therapy, but this may be a costly and not easily accessible option for some people. Another treatment option is pharmacotherapy with antidepressants, though you will need to work with your doctor or a psychiatrist.
For chronic dandruff, there are many over-the-counter medications and shampoos. Most of them, like ketoconazole, are available without a prescription. There are also various practical steps you can take, such as avoiding the excessing use of hair styling products and getting moderate sun exposure.
In the rare event that your one-sided hair loss is due to a rare condition like tinea capitis or lichen planus, a dermatologist will prescribe the best course of treatment.
3. Support Your Hair’s Overall Health
Once you have identified the specific cause of your one-sided hair loss and have taken appropriate action, the next step is to support the health of your hair and encourage growth on a more fundamental level. There are a number of ways to do this.
Scalp Massage and Stimulation
This is a great treatment option for everyone, whether they suffer from hair loss or not. Head massagers can improve your scalp massaging efforts and stimulate hair growth.
Blood flow is important in the hair growth process. This is because blood not only delivers oxygen and vital nutrients to the hair follicles, but it also removes waste and harmful buildup.
For a long time, the usefulness of scalp massages was met with skepticism, but the times are now changing.
A recent study out of Japan found that scalp massages in healthy men resulted in increased hair thickness after 24 weeks (11). The study also found that the mechanical stimulation provided by the scalp massages resulted in increased expression of hair cycle genes and decreased expressions of genes implicated in hair loss.
Not only is scalp massage a highly effective way of promoting healthy hair, but it is also an easy and low-cost intervention.
To begin, use your fingertips to massage your scalp (paying particular attention to the affected area) for at least 5 minutes each day. You can also use a scalp massager or dermaroller to really get the blood pumping.
Reduce Stress & Remove Hair Loss Triggers
Stress is a common factor in various types of hair loss, like alopecia areata, and is possibly also an aggravating factor in individuals with trichotillomania. There are a number of stress reduction techniques that you can do easily at home. These include Qi breathing, yoga, and self-massage.
Of course, you can also utilize the services of a professional, such as a massage therapist or counselor.
In addition to reducing stress, you will also want to eliminate stressful triggers from your life.
No matter the cause, you do not have to suffer from the effects of irregular thinning and balding. While uneven hair loss can be frustrating, it will usually be treatable through various options.
In addition to these tailored interventions, this article outlines a number of general treatments that will promote healthy hair in all people, whether they are suffering from one-sided hair loss or not.