Link Between AA and Inflammatory Diseases

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Alopecia areata’s (AA) clinical presentation varies widely among individuals, ranging from isolated bald patches (patchy AA) to complete scalp (alopecia totalis, AT) or body hair loss (alopecia universalis, AU). The disease course is unpredictable; some patients experience spontaneous remission, while others endure chronic, relapsing episodes of varying severity and duration. This uncertainty often leads to significant psychological distress.¹

Disease Features and Comorbidities

Recent studies have revealed an association between AA and other chronic inflammatory disorders (CIDs), which may influence disease onset, progression, and prognosis.² These findings are supported by data from a comprehensive analysis of 2,657 patients with AA, predominantly from Central Europe. Participants were recruited through outpatient clinics, dermatology practices, and AA support groups in Germany and Belgium.³

“Our findings suggest that distinct comorbid constellations may indicate AA subtypes with differing prognoses,” researchers behind the study stated. “AA patients with comorbid CIDs, particularly AD, bronchial asthma or Hashimoto's thyroiditis, may benefit from increased clinical monitoring and earlier therapeutic intervention.”

Among this cohort, 53.7% reported at least 1CID comorbidity. Atopic conditions were the most frequent, with 44.5% of participants reporting atopic dermatitis (AD, 26.7%), bronchial asthma (13.4%), and/or rhinitis (26.7%). Additionally, 17.4% of patients had non-atopic CIDs, such as Hashimoto's thyroiditis (6.1%), vitiligo (4.6%), psoriasis (2.7%), and rheumatoid arthritis (1.7%).

Influence of Comorbidities on AA Characteristics

The study's findings suggest that comorbidities significantly impact the clinical features of AA:

Early-Onset AA: Patients with comorbid AD, bronchial asthma, or Hashimoto's thyroiditis were found to be more likely to develop AA before the age of 20. Early-onset AA was particularly common in patients with multiple atopic conditions, such as AD, bronchial asthma, and rhinitis.

Severity and Duration: Severe AA, characterized by AT, AU, or a combination of both, was found to be more frequent among patients with comorbid AD, bronchial asthma, or Hashimoto's thyroiditis. Additionally, prolonged AA (episodes lasting over 2 years) was associated with comorbid rhinitis or vitiligo. Bronchial asthma was the most strongly correlated with severe and prolonged disease.

Immune Pathophysiology: While AA is traditionally viewed as a Th1-mediated autoimmune disorder, researchers stated evidence suggests that the Th2 immune axis may also play a role, particularly in patients with atopic comorbidities. This dual immune involvement may contribute to a more severe disease course and poorer outcomes.

Clinical Implications

The study found the presence of comorbid CIDs appears to define distinct AA subtypes with unique prognoses. For example, patients with atopic conditions or Hashimoto's thyroiditis face an increased risk of early-onset, severe, and prolonged AA. These findings underscore the importance of comprehensive clinical assessments that include evaluations for potential comorbidities.

Researchers suggested early identification of CID comorbidities may allow for tailored therapeutic approaches and closer monitoring of high-risk patients. Moreover, understanding the role of immune dysregulation in AA could guide the development of targeted therapies aimed at modulating Th1 and Th2 pathways.

Conclusion

AA is a complex autoimmune disorder with variable clinical outcomes. The study found the presence of comorbid inflammatory conditions, particularly atopic and autoimmune diseases, significantly influences its onset, severity, and duration. By recognizing these associations, researchers behind the study stated clinicians can better stratify patients based on risk and implement proactive management strategies to improve long-term outcomes. They suggested further research is warranted to explore the underlying mechanisms linking AA with its comorbidities and to refine treatment protocols accordingly.

References

1. Muntyanu A, Gabrielli S, Donovan J, et al. The burden of alopecia areata: A scoping review focusing on quality of life, mental health and work productivity. J EurAcad Dermatol Venereol. 2023. doi:10.1111/jdv.18926
2. Lee S, Lee H, Lee CH, Lee WS. Comorbidities in alopecia areata: A systematic review and meta-analysis. J Am Acad Dermatol. 2019;80(2):466-477.e16. doi:10.1016/j.jaad.2018.07.013
3. Friedrich A, Schmitz MT, Gossmann Y, et al. Comorbid bronchial asthma, atopic dermatitis and Hashimoto's thyroiditis are risk factors for early-onset, severe and prolonged alopecia areata. Allergy. 2025. doi:10.1111/all.16468