Could Hayfever Be Linked To Hair Loss? New Research Explores The Connection

By Dr Gwen Adey BDS MFDS RCS

For many years, androgenetic alopecia (male and female pattern hair loss) was viewed largely as a hormonal and genetic condition.

DHT. Genetics. Hair follicle miniaturisation.

That was considered the core story.

But over the last decade, researchers have increasingly started looking at another possible piece of the puzzle: inflammation.

A newly published 2026 study in the World Allergy Organization Journal adds to this growing area of research by exploring whether allergic rhinitis (commonly known as hayfever) may be associated with an increased risk of androgenetic alopecia.

Importantly, the study does not prove that hayfever causes hair loss, nor does it prove that antihistamines prevent it. However, it raises some genuinely interesting questions about the role of immune signalling, histamine pathways and prostaglandins in hair follicle biology.

What Did The Study Find?

Researchers analysed health data from Taiwan’s National Health Insurance database, covering more than 1.6 million individuals between 2000 and 2021.

After matching groups for various confounding factors, they found that individuals with allergic rhinitis had a significantly higher rate of androgenetic alopecia compared to controls.

The study also observed that patients with allergic rhinitis who used second-generation antihistamines appeared to have a lower incidence of androgenetic alopecia than those who did not.

The effect appeared strongest in younger individuals.

Again, this does not prove antihistamines are a treatment for androgenetic alopecia. Observational studies can identify associations, but they cannot establish direct cause and effect.

The authors themselves repeatedly emphasised this limitation throughout the paper.

Why Might Hayfever and Hair Loss Be Linked?

One of the most interesting aspects of this study is the biology behind it.

Researchers are becoming increasingly interested in the idea that at least some forms of androgenetic alopecia may involve chronic low-grade inflammation around hair follicles.

This is sometimes referred to as microinflammation.

In androgenetic alopecia, inflammatory cells have been identified around affected follicles, alongside changes in signalling molecules involved in immune regulation and tissue remodelling.

Meanwhile, hayfever is also an inflammatory condition — involving mast cells, histamine release, eosinophils and Th2 immune signalling.

The study proposes that these overlapping inflammatory pathways may help explain the association.

The Prostaglandin Connection

One particularly interesting molecule discussed in the paper is prostaglandin D2 (PGD2).

PGD2 has attracted significant attention in hair loss research because elevated levels have previously been identified in balding scalp tissue.

Current evidence suggests PGD2 may help push hair follicles into the catagen (regression) phase of the hair cycle and suppress normal follicle activity.

The authors discuss how allergic inflammation may also involve abnormal PGD2 signalling, potentially creating an overlapping biological pathway between hayfever and androgenetic alopecia.

This is still an evolving area of research, but it supports the idea that androgenetic alopecia may be more biologically complex than simply “too much DHT.”

So… Do Antihistamines Help Hair Loss?

This is where caution is important.

The answer currently is:

We do not know.

This study was observational. It cannot prove that antihistamines reduced hair loss risk directly. There may be other explanations for the findings, including unmeasured lifestyle or health differences between groups.

The authors themselves state that the observed associations may reflect residual confounding rather than direct biological effects.

However, the paper does add to growing scientific interest in inflammatory pathways in androgenetic alopecia.

Some antihistamines — particularly cetirizine — have previously attracted attention in small studies because of possible effects on prostaglandin signalling.

That does not mean they are established hair loss treatments.

At present, antihistamines are not FDA-approved treatments for androgenetic alopecia.

Why This Matters

Perhaps the most important takeaway from this study is not “take antihistamines for hair loss.”

It is that androgenetic alopecia may involve far more than hormones alone.

Different people likely have different biological drivers contributing to their hair loss:

• androgen sensitivity

• inflammatory signalling

• prostaglandin activity

• fibrosis

• genetics

• metabolic factors

• scalp environment

• immune pathways

This may partly explain why treatments work well for some individuals and poorly for others.

It is also one reason why personalised approaches to hair loss assessment are becoming increasingly interesting.

For example, genomic tests such as TrichoTest analyse certain pathways related to hair biology — including prostaglandin-related signalling — to help explore why treatment responses may vary between individuals.

Importantly, no genetic test can guarantee treatment success or failure. But studies like this support the broader idea that androgenetic alopecia is biologically heterogeneous rather than identical in every patient.

Final Thoughts

This was a large and well-conducted population study, and the findings are biologically plausible.

However, it is important not to overinterpret the results.

The study does not prove:

• hayfever causes androgenetic alopecia

• antihistamines prevent hair loss

• antihistamines regrow hair

• 
  

What it does do is strengthen the growing scientific discussion around inflammation, immune signalling and prostaglandins in hair follicle biology.

And that is an area of hair loss research that is becoming increasingly difficult to ignore.

Authored by Dr Gwen Adey

First published May 2026

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