Narcolepsy in Alopecia areata: Is there an association?

Narcolepsy in AA

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). It 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 (Ioss of muscle control): Narcolepsy with Cataplexy ("N+C" form or type 1 form) and Narcolepsy without Cataplexy ("N-C" form or type 2 form). The "N+C" form is now understood to be due to an autoimmune reaction destroys the brain’s 70,000 hypocretin 1 and hypocretin 2-producing cells. Hypocretin is a chemical (neurotransmitter) in the brain that is important for regulating wakefulness. Hypocretins 1 and 2 is also called orexin A and B. 

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 HLA allele DQB1*0602 has been proposed. 

The cause of the "N-C" form (type 2 form) is remains poorly understood.

Reports of Narcolepsy in Alopecia areata

As reported in an earlier article,  sleep quality does not appear to be different 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.

Sleep Quality in Patients with AA

However, these studies of course are small (105 patients) and such studies do not have the ability to capture rare associations. One such rare association may be narcolepsy. 

Alopecia areata and Narcolepsy

Both type 1 and type 2 narcolepsy has been reported in association with AA. 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 3 patients with alopecia areata were described to also have 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 2 additional cases of narcolepsy seen in association with alopecia areata.  Nigam and colleagues reported a male with type 1 narcolepsy. 

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.