A large number of patients with alopecia areata still need to be examined to confirm whether an increased prevalence of these conditions exists among patients with alopecia areata. Unfortunately, most studies are performed on small groups; therefore, the data should be interpreted carefully.
Atopic dermatitis is seen in 9-26% of patients with alopecia areata. In the general population, the prevalence of atopic dermatitis in children in temperate developed countries varies from 5-20%. In adults, the prevalence decreases to 2-10%. Some authors have found atopy to be a poor prognostic factor for alopecia areata.
Vitiligo is seen with an incidence varying from 1.8-3% compared with 0.3% in control subjects.
Clinically evident thyroid disease was found in 0.85% of 1700 patients with alopecia areata. The prevalence of thyroid disease determined on a clinical or laboratory basis varies among studies from 0.85-14.7%. The incidence of thyroid disease in control subjects is estimated to be 0.17-2%. The presence of microsomal antibodies is found in 3.3-16% of patients. Antibodies can be found with or without signs or symptoms of thyroid disease, but patients with positive autoantibodies have a higher incidence of functional abnormalities found on thyroid-releasing hormone tests (26% vs 2.8%). The incidence of thyroid microsomal and thyroglobulin antibodies in control subjects is 7%. Other studies have not supported these results. A study in 100 patients with alopecia areata failed to find an increased incidence of circulating autoantibodies, including mitochondrial and thyroglobulin antibodies.
Collagen-vascular diseases have been found in 0.6-2% of patients with alopecia areata, while the incidence in control subjects is 0.17%. The incidence of alopecia areata in 39 patients with lupus erythematous was 10% in a study by Werth et al, in contrast to 0.42% of general dermatologic patients.
Diabetes mellitus was found to be more common in control subjects (1.4%) than in patients with alopecia areata (0.4%). The occurrence of alopecia areata may protect against the appearance of type I diabetes mellitus. However, the incidence of type I diabetes mellitus was significantly higher in relatives of patients with alopecia areata compared with the general population.
Alopecia areata is seen in 6-8.8% of patients with Down syndrome, but only 0.1% of patients with alopecia areata have Down syndrome. The high frequency of alopecia areata in patients with Down syndrome suggests that a genetic linkage for alopecia areata may exist on chromosome 21.
Anxiety, personality disorders, depression, and paranoid disorders are seen with increased prevalence varying from 17-22% of patients, and the lifetime prevalence of psychiatric disorders is estimated to be 74% in patients with alopecia areata. Psychiatric problems are seen in both children and adults. No association has been made between the severity of the psychiatric disorder and that of alopecia areata.
Stressful life events within the 6-month period preceding episodes of alopecia areata were significantly higher in patients with alopecia areata compared with patients with androgenetic alopecia or tinea capitis. Major stress factors (eg, death in family) were reported in 12% of patients.
Others associations in some studies include pernicious anemia, myasthenia gravis, ulcerative colitis, lichen planus, and Candida endocrinopathy syndrome.
A precipitating factor can be found in 15.1% of patients with alopecia areata. Major life events, febrile illnesses, drugs, pregnancy, trauma, and many other events have been reported, but no clear conclusions can be drawn. Despite these findings, most patients with alopecia areata do not report a triggering factor preceding episodes of hair loss.
- Puavilai S, Puavilai G, Charuwichitratana S, Sakuntabhai A, Sriprachya-Anunt S. Prevalence of thyroid diseases in patients with alopecia areata. Int J Dermatol. 1994 Sep. 33(9):632-3. [Abstract].
- Werth VP, White WL, Sanchez MR, Franks AG. Incidence of alopecia areata in lupus erythematosus. Arch Dermatol. 1992 Mar. 128(3):368-71. [Abstract].
- Wang SJ, Shohat T, Vadheim C, Shellow W, Edwards J, Rotter JI. Increased risk for type I (insulin-dependent) diabetes in relatives of patients with alopecia areata (AA). Am J Med Genet. 1994 Jul 1. 51(3):234-9. [Abstract].
- Perini GI, Veller Fornasa C, Cipriani R, Bettin A, Zecchino F, Peserico A. Life events and alopecia areata. Psychother Psychosom. 1984. 41(1):48-52. [Abstract].