Losing hair is a normal part of life. The hairs you see on your brush, in the bathtub drain, or on your pillow are usually no cause for concern. In order for your hair follicles to produce new hair strands, old ones need to fall first. This occurrence, known as hair shedding, is the final stage in the hair growth cycle.
But hair shedding can also occur in excessive amounts. If you notice that you’re suddenly losing a lot more hair than you usually would, you could be experiencing a hair loss symptom known as diffuse hair thinning.
Rather than hair loss associated with any specific part of your head, diffuse thinning occurs evenly across your entire scalp. People experiencing diffuse hair loss tend to find that their scalp coverage is reduced and that their hair has lost volume, making their hair seem a lot thinner than usual.
Is diffuse thinning normal?
According to the American Academy of Dermatology Association, most people shed between 50 and 100 hair strands each day. It’s only when hair shedding exceeds that amount that it may be cause for concern.
If you’re losing hundreds of hairs each day – and your hair loss isn’t centered around a certain part of your head – you’re likely experiencing diffuse hair shedding. This type of hair shedding is a symptom of alopecia (the formal name for a hair loss disorder).
What causes diffuse hair thinning?
Diffuse hair thinning can be associated with multiple types of alopecia. Many people with diffuse thinning are likely experiencing a type of alopecia known as stress-related hair loss. However, people may also see diffuse hair loss following chemotherapy, or as a symptom of conditions like androgenetic alopecia (pattern hair loss) or alopecia areata (an autoimmune form of hair loss).
Diffuse thinning and telogen effluvium
The most common condition associated with diffuse hair thinning is telogen effluvium, which is commonly referred to as stress-related hair loss. According to an article in the Indian Journal of Dermatology, Venereology, and Leprology, people usually see diffuse thinning due to telogen effluvium a few months after the occurrence of the stressful event.
This study and the American Academy of Dermatology Association say that telogen effluvium can be caused by a number of different mental, physical, and environmental stressors. For example, telogen effluvium can be caused by mental stressors, like the COVID-19 pandemic, divorce, or losing your job. Undergoing a surgical procedure, spiking a very high fever, starting a new medication, and not eating regular healthy meals (and ending up with a nutrient deficiency) are all physical stressors that can also trigger this type of hair loss.
Telogen effluvium can also be due to a combination of stressors. For example, working long hours in a big city – a place with a lot of environmental pollution and light pollution that might disrupt your sleep – could also be a cause. Some people are even prone to seasonal telogen effluvium that occurs when the amount of ultraviolet sunlight they’re exposed to changes!
Telogen effluvium affects the hair growth cycle
On a healthy human head, 86 percent of a person’s hair follicles are actively producing growing hairs. These hairs are in the anagen phase (or growth phase), where they remain for around 3 to 5 years.
The remaining 14 percent of hairs are in either the catagen phase (1 percent) or the telogen phase (13 percent). The catagen phase is when hair follicles shrink and change before they enter the telogen phase, while the telogen phase – also known as the rest phase – is the final stage that ends with the hair strand falling out.
In telogen effluvium, these ratios change, reducing the amount of hairs in the anagen phase and increasing the number of hairs in the telogen phase. Only about 70 percent of hairs are growing, while about 30 percent are resting. This is what leads to the increase in hair shedding.
While telogen effluvium typically causes about 300 hairs a day to be lost, according to a study in the journal Clinical, Cosmetic, and Investigational Dermatology, some people may lose as much as 1,000 hairs a day or more. The only way to stop this type of hair loss is to resolve the issue that triggered it in the first place.
How do you stop diffuse thinning?
When stressful events occur, the hair growth cycle is disrupted. But the exact way in which it’s disrupted can vary based on what triggered this hair loss symptom in the first place. This essentially means that some causes of telogen effluvium can resolve on their own, while others may require bloodwork and in-depth health analyses to figure out what’s causing the problem.
If you’ve had a recent medical procedure, recovered from an illness, or suffered shock due to sudden emotional or physical trauma, the trigger that caused your telogen effluvium is now in the past. While you will experience a brief bout of diffuse thinning over 3 to 6 months, your symptoms should resolve themselves, and your hair should start to grow back shortly after.
But if your telogen effluvium has a more complicated cause – like a nutrient deficiency or the impact of the COVID-19 pandemic on your mental health – your hair loss is unlikely to get better until you’ve resolved the underlying issue. If your trigger is a mental stressor, you should consider seeking counseling or trying talk therapy. If it’s physical, talk to your doctor or a dietitian and identify what you can do to improve your body’s well-being.
In certain cases, your healthcare practitioner may recommend that you try using minoxidil, a topical hair loss medication. This drug is FDA-approved for the treatment of pattern hair loss, but is sometimes also used off-label to encourage hair follicles to produce new hair strands.
Diffuse thinning and alopecia areata
Alopecia areata is an autoimmune form of hair loss. It occurs when your body’s immune system attacks your hair follicles. According to StatPearls Publishing, this type of alopecia typically causes people to lose hair in random, circular patches across their scalp.
However, alopecia areata can also affect the entire scalp and may even affect the entire body! These rarer forms of alopecia areata are known as alopecia totalis and alopecia universalis, respectively.
Diffuse alopecia areata
Most people with alopecia areata will not lose all of their hair, so they are unlikely to experience diffuse thinning. But people with alopecia totalis and alopecia universalis are both likely to see diffuse thinning when they first start seeing hair loss symptoms. Unfortunately, diffuse hair thinning caused by alopecia totalis or universalis can rapidly worsen, causing complete baldness.
Stress can also exacerbate symptoms of alopecia areata. A study in The Journal of Medicine and Life says that both environmental and emotional stressors can contribute to alopecia areata. And it’s possible for someone with alopecia areata to experience both this type of hair loss and telogen effluvium simultaneously. It may even be possible for this stress to be one of the triggers that prompts people with alopecia areata to develop the more extensive hair loss seen in alopecia totalis or alopecia universalis.
Alopecia areata can be treated with immunotherapy or immunosuppressants, but these treatments don’t work for everyone. And diffuse alopecia areata is particularly challenging to treat. Less than 10 percent of people fully recover from alopecia totalis and alopecia universalis.
Diffuse thinning and androgenic alopecia
Androgenic alopecia, also known as pattern baldness, is the most common cause of hair loss. This genetic and hormonal condition causes people to lose hair in a certain pattern before eventually resulting in complete hair loss at the top of the head.
According to a study in the Journal of Cutaneous and Aesthetic Surgery, people with this condition are likely to see a number of hair loss symptoms, including a receding and changing hairline, hair loss at their temples, and thinning at the crown of their head. But one of the main symptoms that occurs is thinning hair.
The thinning hair seen in androgenic alopecia is different to the diffuse thinning that occurs in telogen effluvium and alopecia areata. In these conditions, the volume of your hair is changing – making your ponytail thinner or your scalp more visible.
But in androgenic alopecia, your individual hair strands are actually shrinking and becoming thinner. While this may initially have the same effect in appearance as diffuse thinning, it’s the diameter of each hair strand that changes as androgenic alopecia progresses. This phenomenon is known as miniaturization.
Hair miniaturization gets increasingly worse, causing hairs to become thinner and weaker over time. Eventually, without a hair loss treatment, hair follicles completely stop producing hair and become dormant, leading to hair loss. The good news is that androgenic alopecia is gradual and progressive – it takes years for people to go bald.
The bad news is that, like with alopecia areata, it’s possible for people to experience hair loss due to telogen effluvium and androgenic alopecia simultaneously. So you may actually be seeing both diffuse thinning and miniaturization simultaneously.
Androgenic alopecia vs. telogen effluvium
If you’re not certain if you’re experiencing telogen effluvium or androgenic alopecia, the easiest way to tell is to count the hairs you’re shedding. According to the study in the Clinical, Cosmetic, and Investigational Dermatology journal, people with androgenic alopecia usually shed between 10 and 100 hairs every few days. In contrast, individuals with telogen effluvium tend to shed between 300 and 1,000.
If you’re shedding over 100 hairs and are still not so sure what’s going on, another strategy is to measure the length of the hairs you’re shedding. If you see that many hairs are shorter than 3 centimeters, you’ve likely identified a sign of androgenic alopecia. Losing hundreds of hairs and finding that 10 percent (or more) are 3 centimeters or less is likely a sign of both telogen effluvium and pattern hair loss.
Does hair stop thinning?
Hair affected by androgenic alopecia won’t stop thinning on its own. The only way to counteract this symptom is to use a hair loss treatment like minoxidil, low-level laser therapy, or finasteride. All three of these are FDA-approved hair loss treatments for androgenic alopecia, but according to StatPearls Publishing, they all work in different ways.
Finasteride targets the hormonal component of androgenic alopecia, which is actually the part responsible for hair miniaturization. While this makes it a particularly good treatment for pattern hair loss, it won’t help if you have both androgenic alopecia and telogen effluvium.
Minoxidil works by widening blood vessels, allowing more blood, oxygen and nutrients to reach hair follicles. Laser hair therapy acts as a biostimulatory light treatment, helping boost hair growth. According to StatPearls Publishing and a study in the European Journal of Molecular & Clinical Medicine, both of these treatments are likely to help treat both pattern hair loss and stress-related hair loss. However, if your telogen effluvium is caused by an underlying health condition or long-term stressor, you’ll still need to address this in order for the issue to go away.
Is diffuse thinning reversible?
Diffuse hair thinning is a reversible hair loss symptom most often associated with telogen effluvium. It’s indicative of a disruption to the hair growth cycle. In many cases, this type of hair loss can resolve on its own without any treatment.
However, it’s possible for diffuse hair loss to be caused by a number of other factors, like an underlying health issue, dietary changes, or new medications. In such cases, the cause behind telogen effluvium needs to be identified and resolved before the hair growth cycle can return to normal.
It’s also possible for diffuse thinning to be associated with other hair loss disorders, including alopecia areata and androgenetic alopecia. Telogen effluvium can happen simultaneously and worsen hair loss symptoms in both cases. While diffuse alopecia areata is challenging to treat successfully, combined telogen effluvium and androgenetic alopecia can be treated with minoxidil and low-level laser therapy.