Is there an association between Narcolepsy and Alopecia Areata?
Narcolepsy is a sleep disorder that is characterized by excessive sleepiness, sleep attacks, sleep paralysis, hallucinations and, for some, the sudden loss of muscle control (cataplexy). The “classic tetrad” of symptoms is excessive daytime sleepiness (EDS), cataplexy, hypnagogic hallucinations, and sleep paralysis. The disease affects roughly 1 in every 2,000 people but can go undiagnosed for many years.
Narcolepsy is poorly understood. However, it is now recognized that there are two main forms of narcolepsy depending on whether the patient has cataplexy (which means Ioss of muscle control):
Narcolepsy with Cataplexy ("N+C" or type 1 form)
Narcolepsy without Cataplexy ("N-C" or type 2 form).
The "N+C" form (type 1 form) is now understood to be due to an autoimmune reaction that destroys the brain’s 70,000 hypocretin 1 and hypocretin 2-producing cells. Hypocretin is a chemical (neurotransmitter) in the brain that regulates “wakefulness.” Hypocretins 1 and 2 are also called orexin A and B. The N+C form (type 1) was recently reported to be associated with an increased risk of a variety of autoimmune diseases - including alopecia areata, thyroid disease and rheumatoid arthritis.
Narcolepsy may, therefore, be a true autoimmune disease. The recent discovery of a link between narcolepsy and a gene for a component of the T cell receptor supports this theory. A link to the HLA allele DQB1*0602 has been proposed.
The cause of the "N-C" form (type 2 form) remains poorly understood.
Reports of Narcolepsy in Alopecia areata
Some studies have suggested that sleep quality is similar in patients with alopecia areata compared to the general population. This is based on 2014 studies by Inui and colleagues published in the International Journal of Dermatology. However, these studies were small (105 patients) and could not capture rare associations. One such rare association may be narcolepsy.
Alopecia areata and Narcolepsy
Both type 1 and type 2 narcolepsy have been reported in association with alopecia areata. One of the first reports of an association between alopecia areata and narcolepsy occurred in 1992 in the Spanish language medical literature. This was a report by Dominguez Ortega in which three patients with alopecia areata were also described as having narcolepsy. The diagnosis in these three patients was made with a multiple sleep latency test. In 2010, Lloyd King and colleagues from Vanderbilt University reported two additional cases of narcolepsy seen in association with alopecia areata. Nigam and colleagues reported a male with type 1 narcolepsy.
Final Summary
Patients with narcolepsy may have an increased risk of alopecia areata.
References*
Nigam G, et al. Alopecia areata and narcolepsy: a tale of obscure autoimmunity. BMJ Case Rep. 2016.
Domínguez Ortega L. [Narcolepsy and alopecia areata: a new association?]. An Med Interna. 1992.
King LE Jr, et al. A potential association between alopecia areata and narcolepsy. Arch Dermatol. 2010.
Inui et al. Sleep quality in patients with alopecia areata: questionnaire-based study. Int J Dermatol. 2014.
Martinez-Orozco FJ et al. Long-Term Outcome of a Series of Patients With Narcolepsy Type 1 and Comorbidity With Immunopathological and Autoimmune Diseases. J Clin Med Res . 2022 Aug;14(8):309-314. doi: 10.14740/jocmr4758. Epub 2022 Aug 27.