Medically reviewed by Kristin Hall, FNP
Written by Our Editorial Team
Last updated 8/12/2021
Most hair loss in men is caused by androgenetic alopecia, or male pattern baldness. However, a variety of other issues can also affect your hair’s ability to grow and contribute to hair loss.
One of the lesser well-known hair abnormalities that causes hair loss is loose anagen syndrome (LAS), a type of hair disorder that can cause your hair to become “loose” in your scalp and easy to pull out.
Loose anagen syndrome is most common in children, but it can also affect adults. When it does occur, it can cause diffuse hair loss that gives your hair a thin appearance.
The good news is that it doesn’t ordinarily result in complete hair loss.
Below, we’ve explained what loose anagen syndrome is, as well as the factors that can cause it to develop.
Loose anagen syndrome, or loose anagen hair, is a hair growth disorder. People with LAS have hairs that are loosely anchored to the scalp, allowing them to fall out easily and painlessly when pulled.
Your hair grows as part of a multi-stage process that’s referred to as the hair growth cycle. Hairs grow from the hair follicles to their full length in the anagen phase of this process, which typically lasts for two to six years.
Normal anagen hair, after reaching its full length, passes through the catagen (transition) and telogen (rest) phase before fully detaching from the scalp and shedding, with a new hair taking its place.
In people with loose anagen syndrome, hairs in the anagen phase don’t properly anchor into the scalp.
Because of this weak bond, hairs can be pulled from the scalp easily or simply fall out as a result of styling or hair care.
Loose anagen syndrome is most common in children, particularly girls. However, it also affects adults.
Loose anagen syndrome typically causes diffuse hair loss, giving the hair a thin look and a messy, “bed head” pattern.
Researchers aren’t precisely aware of how loose anagen hair syndrome develops, or the factors that may cause this hair condition to affect specific people.
Currently, most research suggests that loose anagen syndrome occurs due to an abnormality in the hair’s natural mechanism for anchoring into the scalp.
More specifically, experts think that loose anagen syndrome is caused by defects that affect the growth of the inner root sheath -- one of the first parts of the hair shaft to grow out from the hair follicle.
Hair grows through a process called keratinization, in which cells produce large amounts of the protein keratin. The inner root sheath is the first layer of the hair to keratinize.
When the inner root sheath is developed too early -- an issue called premature keratinization -- it may result in a weaker bond between the cuticle of the inner root sheath and the cuticle of the hair shaft.
This weak bond reduces the strength of the hair, making it easier to pull out, either accidentally or deliberately, from the scalp.
In one study, researchers found that loose anagen hairs could be pulled out from the scalp with less than a third of the force required to pull out healthy hair.
It affects around two out of every million people per year and either occurs spontaneously or as a result of one or several inherited genes.
Although loose anagen syndrome usually occurs on its own, it can sometimes occur with other hereditary or developmental disorders, including:
Ectodermal dysplasia, ectrodactyly and cleft lip/palate syndrome
Hypohidrotic ectodermal dysplasia (HED)
Uncombable hair syndrome
Because loose anagen syndrome isn’t common, it’s often mistaken for other hair growth issues or conditions that can cause hair shedding.
The primary symptom of loose anagen syndrome is hair that’s weakly attached to the scalp and easy to pull out.
Cases of loose anagen syndrome are typically sorted into three categories:
Type A. People with this type of LAS have spare, short hair that can appear overly thin due to reduced hair density.
Type B. People with this type of LAS have curly, patchy and sparse hair that’s difficult to control. This type of hair is often described as looking unruly, or as having a “bed head” appearance.
Type C. People with this type of LAS have hair that presents with normal thickness and density, but sheds excessively. This type of loose anagen syndrome occurs in adults.
Unlike male pattern baldness or scarring hair loss, which cause permanent damage to your hair follicles, loose anagen syndrome usually causes temporary hair loss.
Most cases of loose anagen syndrome only affect the scalp hair, with the eyelashes, eyebrows and body hair normal in strength and appearance.
If you think you may have loose anagen syndrome, it’s best to talk to your healthcare provider or schedule an appointment with a dermatologist.
Most of the time, a dermatologist will be able to diagnose loose anagen hair syndrome following a brief physical examination.
To test your hair for LAS, a dermatologist may do the following:
Carry out a hair pull test to see if your hair can be extracted from your scalp easily and without significant pain.
Perform a microscopic examination of hairs pulled from your scalp (trichogram) to look for signs of loose anagen syndrome, such as misshapen hair bulbs, ruffled cuticles and absent inner or outer root sheaths.
You’ll generally be diagnosed with loose anagen hair syndrome if a majority of your extracted hairs show signs of abnormal development.
Most of the time, loose anagen hair syndrome improves on its own and doesn’t require active treatment.
If you have noticeable hair shedding from LAS, your healthcare provider may suggest using a topical hair loss medication such as minoxidil.
Minoxidil works by stimulating blood flow and prolonging the anagen phase of the hair growth cycle.
Although it usually takes several months to produce improvements, it’s considered an effective first-line therapy for loose anagen syndrome.
To prevent loose anagen hairs from falling out, your healthcare provider may suggest that you wash and dry your hair gently.
It may also help to avoid hairstyles that put tension on the roots of your hair.
Loose anagen syndrome is an uncommon hair growth disorder that can cause your scalp hairs to fall out easily and give your hair a thin appearance.
If you think you might have loose anagen syndrome, it’s best to talk to your healthcare provider or schedule an appointment with a dermatologist.
You can learn more about conditions that cause hair loss in our detailed guide to the causes of hair loss in men.
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