What Are JAK Inhibitors And How Can They Help You?

January 18, 2019

A man suffering from alopecia universalis has recently had a dramatic turnaround after starting a medication. By taking a JAK inhibitor he was able to grow his hair back! In this blog we discuss what a JAK inhibitor is and what the current research around hair loss and JAK inhibition is.

Alopecia areata affects 0.1%-0.2% of people worldwide. Unlike hormone related hair loss, Alopecia areata is caused by your immune system incorrectly targeting your hair and making it fall out. JAK (janus kinase) inhibitors, are medications used to suppress the immune system and are sometimes given to patients who are suffering from autoimmune conditions like Psoriasis. For a while they have been known to help regrow hair for those who are sufferers of alopecia areata.

Alopecia areata

Alopecia areata is a type of hair loss caused by the immune system. The hair on your head is typically protected from your immune system. This means your natural immune cells wouldn’t normally attack your hair. However, in some people this process can be altered and your immune system can incorrectly start to target your hair, making it fall out over a short period of time. The hair loss can happen in small circular patches often seen in alopecia areata.

Alopecia totalis

This is similar to alopecia areata, where hair is targeted by the immune system, but hair loss occurs all over the face (scalp and facial hair).

Alopecia universalis

This is again similar to alopecia areata but hair loss happens all over the face and body.

You might notice you suffer from alopecia areata/ totalis or universalis if you have a family member who suffers from the condition or if you have the following conditions:

Autoimmune thyroid disease
Systemic lupus erythematosus
Vitiligo

This is because there is overlap between the immune response in these conditions and the immune system targeting hair in alopecia areata/ totalis and universalis.

What is the link between JAK and alopecia areata?

JAK is a protein in your body that helps signal a response to your immune cells. By overstimulating this signal your immune cells can start to target your hair follicles and cause them to fall out. Research has shown that preventing JAK signalling can have following effects in mice hair (2,3,4):

Prolonging the hair growth phase (anagen)
Promoting hair regrowth
Increasing blood supply to hair follicles

This essentially suggests that if you have an overactive JAK signal then you seem to suffer from alopecia areata, alopecia totalis and alopecia universalis.

What is the evidence for medications so far?

There are a few JAK inhibiting medications that have been used to treat alopecia areata.

Tofacitinib and ruxolitinib have both been seen to be effective in treating severe alopecia areata. Their side effects weren’t major and could be treated in most cases. However, the medications haven’t been put through trials and the evidence is mainly from a few cases. Secondly, the medications weren’t taken long term so there is no evidence around how effective JAK inhibiting treatments could be when someone stops taking them. So, although these medications have been shown to be effective more research needs to be carried out. More trials need to be carried out on people to gather further evidence on their effectiveness and safety. Also, JAK inhibiting medications can dangerously suppress your immune system, making you at risk of severe infections. Juggling this risk against hair loss needs to be a considered decision.

In conclusion, JAK inhibiting medications do provide an exciting prospect for the future development of new treatments for alopecia areata/ totalis and universalis. The evidence for them so far as been their use in the short term for a few number of patients. More evidence needs to be collected around how effective they are in the long term and in many more patients.

What treatments are currently available?

Currently the only licensed and proven medications for hair loss include Finasteride and Minoxidil. Both these medications wouldn’t work in alopecia areata/ totalis and universalis as they don’t target the immune system. If you are suffering from autoimmune alopecia it is important you seek advice from a hair loss specialist or a hair transplant surgeon who can advise you what your best course of treatment is. A course of steroid medications may be the best option for you.

References