Is there a connection between allergies and hair loss?

The human body is an amazingly complicated structure of billions of cells which, most of the times, work together in harmony. Unfortunately though, every once in a while there are situations in which not all cells work together in synchrony, causing autoimmune diseases and inflammatory conditions where the cells act up against one another or act excessively over a minute antigen exposure. These situations are extremely troublesome as they disturb the natural balance of the body and impact our general health, not only affecting our internal organs, but also bringing about visible, unwelcome changes in our external appearance too. Inflammatory conditions, such as allergies for example, can in fact have adverse effects on the largest organ of our body, the skin, or, more specifically, on the hair it harbors. Hair, one of the attractive features in our appearance frequently gets affected when something in our immune systems is functioning correctly. So, is there a connection between allergies and hair loss?

What are the common causes of hair loss? 

Alopecia or hair loss is a very common complaint faced by individuals of all ages around the globe. Hair loss can result from multiple pathological conditions and some medical treatments as well. The most common causes of hair loss include genetics, autoimmune, stress-induced, thyroid disease, anemia, protein deficiency, chemotherapy, and low vitamin levels, etc.

What is alopecia areata (AA)? 

A specific subset of alopecia with an autoimmune background is known as alopecia areata. Here hair loss is generally not limited to scalp only and can involve eyebrows, facial hair or any other hairy part of the body. The pattern of hair loss also variates from patchy to generalized

Although autoimmunity is a defined cause for this condition, it is still hypothesized to have a multifactorial origin. With genetics and other environmental factors playing a significant role in the progression and severity of alopecia in patients. It is also associated with diseases of the endocrine glands, various states of stress and emotional shock, vitiligo, and neurodermatitis, and from reflex irritations from focal lesions such as dental abscesses. 

Is there a connection between allergies and hair loss?

In recent studies, allergy has also been proposed to be associated with the progression of alopecia. While following patients with a diagnosed history of alopecia areata it was found that a subset of patients had one or more prevalent allergic conditions. These included atopic rhinitis, asthma, and dermatitis, etc. In many instances, the severity and flares of these allergic conditions correlated with the severity and onset of Alopecia areata. These findings were supported by the fact that both alopecia areata and allergy share a similar genetic background of dysfunctional immune reaction. 

Literature also shows that alopecia areata is associated with atopy in 10–22% of patients, which is two times more prevalent in the general population. On the other hand, a higher risk of allergic diseases is also reported in patients with alopecia areata such as atopic eczema, hay fever, asthma, and rhinitis, etc. in comparison to the general population.

A study conducted on Chinese population concluded that allergy to dust mites can also contribute to early-onset and severity of alopecia areata by affecting the immune system.
Another analytical study conducted in Taxes in 2009 revealed that a history of atopy and autoimmune disease was associated with an increased risk of alopecia areata. These results were found consistent for both A and that the severe subtype of AA (i.e., alopecia totalis and alopecia universalis) and the localized subtype (i.e., AA persistent).

Does this association benefit patients therapeutically?

Yes! This connection between allergies and hair loss can come in handy when treatment options for the condition are to be selected. As a supportive treatment with anti-allergy medication can reduce the severity of alopecia in allergic patients. Also, avoidance of allergens is found to improve the treatment outcomes in these patients.

 

References: 

Zhang X, McElwee KJ. Allergy promotes alopecia areata in a subset of patients. Experimental dermatology. 2019 Sep 3.

Barahmani N, Schabath MB, Duvic M, Registry NA. History of atopy or autoimmunity increases risk of alopecia areata. Journal of the American Academy of Dermatology. 2009 Oct 1;61(4):581-91.

Wasserman D, GuzmanSanchez DA, Scott K, McMichael A. Alopecia areata. International journal of dermatology. 2007 Feb;46(2):121-31.

Muller SA, Winkelmann RK. Alopecia areata: an evaluation of 736 patients. Archives of Dermatology. 1963 Sep 1;88(3):290-7.

Li SF, Zhang XT, Qi SL, Ye YT, Cao H, Yang YQ, McElwee KJ, Zhang X. Allergy to dust mites may contribute to early onset and severity of alopecia areata. Clinical and experimental dermatology. 2015 Mar;40(2):171-6.

De Weert J, Temmerman L, Kint A. Alopecia areata: a clinical study. Dermatology. 1984;168(5):224-9.

Shellow WV, EDWARDS JE, KOO JY. Profile of alopecia areata: a questionnaire analysis of patient and family. International journal of dermatology. 1992 Mar;31(3):186-9.

Ibrahim O, Bergfeld WF, Piliang M. Eosinophilic Esophagitis: Another Atopy-Related Alopecia Areata Trigger?. InJournal of Investigative Dermatology Symposium Proceedings 2015 Nov 1 (Vol. 17, No. 2, pp. 58-60). Elsevier.