The link between sleep and skin condition is increasingly being discussed, but in trichology this factor has long remained in a secondary role. Meanwhile, sleep disturbances potentially affect several systems important for the hair follicle: inflammatory and immune regulation, stress response, and circadian rhythms. The authors of a systematic review published in Dermatology and Therapy (Heidelberg) in November 2025 collected and summarized data on how sleep problems are associated with different variants of hair loss — from alopecia areata and androgenetic alopecia to telogen effluvium and scarring forms [1].

How the study was organized

The work was conducted as a systematic review according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses)—an international reporting standard for systematic reviews. The authors searched PubMed and Scopus (October 2025) for publications without date or language restrictions, using terms for alopecias and sleep disturbances. A total of 474 articles were identified; after removing duplicates and applying selection criteria, 29 studies were included in the final analysis. The evidence base was generally low or moderate (cross-sectional studies predominated), and there were no intervention studies in which the effect of sleep correction on the course of alopecia could be tested.

Sleep was assessed mainly by questionnaires, most often the Pittsburgh Sleep Quality Index (PSQI) and the Epworth Sleepiness Scale (ESS). Objective methods were rarely used; polysomnography was mentioned in only one work. This is an important context: a significant part of the data is based on self-reports and may depend on concomitant factors — stress, anxiety, depression, hormonal fluctuations, and drug therapy.

By nosologies, the studies were distributed unevenly: most data were on alopecia areata (AA) and androgenetic alopecia (AGA), significantly less on telogen effluvium (TE), and there were few publications on scarring forms and traction alopecia.

What the data showed for different variants of hair loss

Alopecia areata

In general, patients with AA more often reported sleep disturbances than the control group. The authors consider the link between sleep and the disease as potentially bidirectional: poor sleep may coincide with increased inflammatory activity and stress response, while hair loss itself can maintain anxiety, stigmatization, and "nocturnal hyperarousal" that interferes with falling asleep [2, 3].

From a biological point of view, the review notes that sleep deprivation is associated with a proinflammatory profile, including changes in IL-6, CRP, and TNF-α levels, as well as activation of immune signaling, which is linked to inflammatory dermatological conditions [4]. In the context of AA, the authors separately highlight immune mechanisms (cytokine activation, possible changes in regulatory T cells), involvement of the stress axis (HPA), and the influence of circadian regulation (including through circadian genes, or "clock genes") on the threshold of autoimmune reactivity around the follicle.

In terms of numbers, in the included studies on AA, the proportion of patients with poor sleep according to PSQI (PSQI≥5) varied in the range of 77–87% (versus 70% in the control). In individual works, worse sleep indicators were more often noted with more severe disease and with comorbid atopic dermatitis, which may reflect the total inflammatory and psychoemotional burden.

Androgenetic alopecia (AGA)

For AGA, the authors identify several pathogenetic lines. One of them is circadian misalignment: the review discusses data on the link between later sleep onset and reduced expression of PER3 (Period Circadian Regulator 3 — one of the key "clock genes" regulating daily biorhythms) with AGA and possible consequences for the "timing" of the follicular cell cycle and growth signals [5].

Another line is obstructive sleep apnea: intermittent hypoxia and oxidative stress are considered as factors potentially associated with changes in systemic androgens and inflammatory mediators and, as a consequence, with androgen-dependent miniaturization.

At the level of observational results, severe AGA was associated with shorter sleep duration (≤6 h), higher PSQI scores, and higher STOP-BANG scores (a questionnaire for assessing the risk of obstructive sleep apnea). However, individual samples (e.g., younger ones) yielded ambiguous results.

Telogen effluvium (TE)

TE is less represented in the review, but the general conclusion fits into the clinical logic of "stress–sleep–diffuse loss." The authors discuss the role of substance P (SP) as a mediator of neurogenic inflammation: SP can promote mast cell degranulation and an enhanced inflammatory response, and experimental data support a bidirectional link between stress-induced neuropeptide shifts and worsening sleep.

In the context of the COVID-19 pandemic, the review also noted a temporal coincidence of TE episodes with an increase in psychosocial stress and insomnia.

Scarring alopecias on the example of lichen planopilaris
In lichen planopilaris, the key contributor to worsening sleep is chronic scalp inflammation — itching, pain, burning — and the psychological burden of the disease [6]. Average PSQI values in patients with lichen planopilaris are higher than in the control group, indicating poorer sleep quality and greater sleep latency (delay).

Traction alopecia

There is almost no separate data block on sleep quality in traction alopecia. Still, a practical point is important: nighttime care and styling habits (for example, hair tension during sleep) are described as potential risk factors for mechanical follicular damage.

Possible mechanisms linking sleep and hair loss

The authors of the systematic review reduce the link between sleep and hair loss to three intersecting levels: neuroendocrine regulation (including the hypothalamic–pituitary–adrenal axis), inflammation/immune activation, and metabolic/circadian factors. It is separately emphasized that sleep disturbances in various studies were associated with changes in inflammatory markers and mediators (in particular, IL-6, CRP, TNF-α), and that the hair follicle is a peripheral neuroendocrine mini-organ sensitive to stress mediators and immune signals.

At the same time, the authors are careful in their formulations: the current database is mainly observational, so it is impossible to talk about causality. But sleep already has clinical significance in at least two scenarios: (1) as a marker of the overall burden of the disease and psychoemotional distress, and (2) as a potentially modifiable factor that can be identified and corrected in parallel with the main therapy.

Conclusions

The limitations of this systematic review are typical for this topic: heterogeneity of designs, predominance of cross-sectional studies, emphasis on self-reported sleep questionnaires, rare use of objective methods, and a large number of possible confounders (stress, psychiatric comorbidity, hormonal variations, medications). And yet, the review clearly shows that sleep disturbances are common across different forms of hair loss and are consistent with biologically plausible mechanisms — including inflammatory activation, the stress axis, and circadian regulation.

The practical minimum is to include a brief sleep screening in the consultation (e.g., PSQI), and, if insomnia or OSA is suspected, to discuss further diagnosis and management as part of comprehensive patient care.

References

1. Boghosian T., Mendez H., Sayegh M. et al. The intersection of sleep and hair loss: a systematic review. Dermatol Ther (Heidelb) 2026; 16: 937–952.
2. Dai Y.-X., Tai Y.-H., Chen C.-C. et al. Bidirectional association between alopecia areata and sleep disorders: a population-based cohort study in Taiwan. Sleep Med 2020; 75: 112–116.
3. Sánchez-Díaz M., Díaz-Calvillo P., Soto-Moreno A. et al. The impact of sleep quality on mood status and quality of life in patients with alopecia areata: a comparative study. Int J Environ Res Public Health 2022; 19: 13126.
4. Irwin M.R., Olmstead R., Carroll J.E. Sleep disturbance, sleep duration, and inflammation: a systematic review and meta-analysis of cohort studies and experimental sleep deprivation. Biol Psychiatry 2016; 80: 40–52.
5. Wu Q., Li M., Xiong Y. et al. Association between sleep patterns, circadian rhythms, and hair loss in young adults. Chronobiol Int 2025; 42: 1395–1405.
6. Wegner É., Koth V., Salum F., Cherubini K. Association between oral lichen planus and sleep quality: a systematic review. Med Oral Patol Oral Cir Bucal 2024; (6): e750-e757.