Relação entre alopecia, estresse crônico e alterações no eixo hipotálamo-hipófise-adrenal: uma revisão integrativa de literatura

Abstract

Hair has a continuous growth cycle characterized by four phases: anagen (growth), catagen (regression), telogen (rest), and exogen (fall). Alopecia, the absence or loss of hair, is classified as non-scarring (reversible) and scarring (permanent). Chronic stress can induce premature transition from the anagen to the telogen phase, lengthening the resting period and causing telogen effluvium, one of the most common non-scarring alopecias. The reviewed literature has shown that high cortisol levels have harmful effects on the hair follicle. Excess of this hormone reduces synthesis and accelerates the degradation of crucial structural components, such as hyaluronic acid and proteoglycans. Given this, the present literature review aimed to analyze the relationship between alopecia, chronic stress, and changes in the hypothalamic-pituitary-adrenal (HPA) axis.The research consists of a descriptive integrative literature review. The keywords hair loss, cortisol, and hypothalamic-pituitary-adrenal axis were used in the PubMed database, with filters for publications from the last 10 years, in which 67 articles were found in the electronic databases. An initial exploratory reading of the titles and abstracts was performed, resulting in the selection of 25 studies. Finally, after reading them in full, 10 articles were selected that fit the theme in question. It became clear that internal and external stressors associated with oxidative stress and inflammatory events contribute significantly to hair loss. The findings demonstrate that cortisol acts as a central mediator in the pathogenesis of stress-induced alopecia, negatively influencing the integrity of structural components of the hair follicle, such as proteoglycans, and promoting the transition from anagen to telogen.