Thyroid Disease and its link to Alopecia Areata
Thyroid disease, which comes in many forms and features numerous symptoms, is often associated with alopecia areata. The two have become linked by the increased cases of hair loss reported by those suffering from thyroid disease, but hair loss symptoms reported are not necessarily cases of alopecia areata – which is synonymous with distinct localised hair loss. It is important then to correctly diagnose thyroid disease and alopecia areata as independent conditions, but recognize their autoimmunal links.
Thyroid disease
The thyroid gland is responsible for a range of unique bodily functions, and can have a significant impact on overall health when it is negatively affected. Most typically associated with controlling metabolism, a malfunctioning thyroid can most substantially impact weight, mood, and energy levels, which all influence various important bodily functions.
With this in mind, researchers have spent many years studying the various impacts of thyroid disease, and looking for ways to successfully treat it. Though the link to alopecia areata is not strong, they do both occur in slightly higher percentages among those who have one or other of the diseases. Researchers have identified a few factors which may contribute to this statistic; most notable are the natural statistical increase in likelihood of developing additional autoimmune diseases (including alopecia areata) and the impact to overall bodily health which can result in reduced hair growth, and increased hair loss.
The relationship between thyroid disease and alopecia areata
Though they do not identify the causal relationship at work, researchers have made some interesting discoveries when studying the relationship between the two diseases. There are a few interesting statistics which demonstrate the link between alopecia areata and thyroid disease. In one study for example, 59 out of 736 patients affected with alopecia areata also suffered from a thyroid disorder (7.9% rate). It was noted by the researchers that these thyroid disorders did occur more frequently in patients who had alopecia areata, although not on a significant level. On average most studies do indicate that about 8% of patients with alopecia areata also have a thyroid disorder. Whereas the general population has a rate of developing alopecia areata of between 0.1% and 0.2%.
As mentioned, the most likely relationship between the two diseases is that both thyroid disorders and alopecia areata are autoimmune diseases. A disease is classed as 'autoimmune' when it involves the body’s own immune system incorrectly targeting the body’s own tissue or cells. Autoimmune diseases are much like an allergy, in that the immune system incorrectly attacks an agent which bears the body no threat. This can result in symptoms which run the gamut of severity, from mild arthritis through to life threatening chronic multiple sclerosis.
In the case of alopecia areata, this takes the form of the body's white blood cells targeting and cutting of the hair follicles, causing them to slow and eventually cease production of hair. In the case of thyroid disease, the immune systems target varies greatly, but typically affects some aspect of thyroid function. It is important to note that the presence of a first autoimmune disease does slightly increase the chances of a person developing a second – though it is by no means inevitable. This does however highlight the key relationship which might lead researchers to associate thyroid disease and alopecia areata.
Theories that attempt to explain the relationship between alopecia areata and thyroid disorders
The exact procedure in which thyroid problems can assist in triggering alopecia areata is not direct. But rather it is the symptoms of a thyroid problem that can lead to developing alopecia areata. The thyroid gland controls many of the body’s functions through the production and regulation of hormones. The specific hormones produced by the thyroid gland regulates how fast the body’s metabolism works and how the body’s cells use energy. This regulation affects the bones, hair, energy levels, body weight and temperature. Thyroid disorders, that are either underactive or overactive, can affect any of the above mentioned functions.
There are two major theories currently present that attempts to explain why alopecia areata occurs more often in patients with a thyroid disorder than not. Using our understanding of how alopecia areata can be triggered and the functions of the thyroid gland, scholars have put together the following two theories:
The first theory argues that the misregulation of how cells use energy and the resulting effect on hair, body weight, and temperature can all have an adverse effect on the immune system. Thus causing an autoimmune reaction, and in the cases of alopecia areata the immune system attacks hair follicles. Which cause the hair follicles to slowly fall out and stop growing. The second theory explains that the direct effect that the thyroid gland has on the growth of hair can influence alopecia areata to occur. It is believed that a dysfunctional thyroid can send confusing messages to the white blood cells to attack hair follicles. And what results is patchy hair loss caused by an immune reaction.
These theories that attempt to explain why alopecia areata and thyroid disease are correlated, are not backed by scientific studies and analysis and that is why they are referred to as theories rather than fact. But these theories are based on our understanding of how the body works and the inferences made can legitimately explain why the the occurrence rate of alopecia areata is much more prevalent in those who have a thyroid disorder than in those who do not.
Conclusion
Though thyroid disorder itself may not directly lead to alopecia areata, it does signal an increased likelihood of developing other autoimmune diseases including alopecia areata. On balance, it appears that the kind of hair loss traditionally associated with thyroid disorder is not always alopecia areata, as it does not involve an autoimmune response or patches of hair loss. Though both diseases cannot be directly linked, it does tell us that those with alopecia areata should check out the health of their thyroid as a precautionary measure.