Hair loss underactive thyroid
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Hair Loss and Underactive Thyroid: Understanding the Connection
Thyroid Hormones and Hair Follicle Function
Thyroid hormones (THs), including triiodothyronine (T3) and thyroxine (T4), play a crucial role in the growth, differentiation, and metabolism of cells throughout the body, including hair follicles. Research has shown that hair follicles express thyroid hormone receptors, indicating that they are direct targets of THs 3. These hormones can influence various aspects of hair biology, such as prolonging the anagen (growth) phase, stimulating hair matrix keratinocyte proliferation, and enhancing hair pigmentation 3.
Hypothyroidism and Hair Loss
Hypothyroidism, a condition characterized by insufficient production of thyroid hormones, has been strongly linked to hair loss. This condition can lead to widespread hair shedding, a phenomenon observed in both hyperthyroidism and hypothyroidism 1. The impact of hypothyroidism on hair loss is significant, as it can alter the structure and function of hair follicles, leading to conditions such as telogen effluvium, where hair prematurely enters the resting phase and falls out 1.
Prevalence of Thyroid Dysfunction in Hair Loss Patients
Studies have highlighted the prevalence of thyroid dysfunction among patients experiencing diffuse hair loss. In a cross-sectional study involving female patients with diffuse hair loss, a significant number of cases were found to have abnormal thyroid function. Specifically, 16.6% of patients with associated systemic diseases had thyroid disorders, including overt hypothyroidism and subclinical hypothyroidism 2. This underscores the importance of evaluating thyroid function in patients presenting with diffuse hair loss, as thyroid dysfunction could be an underlying cause 2.
Mechanisms of Thyroid Hormone Action on Hair Follicles
The mechanisms by which thyroid hormones affect hair follicles are multifaceted. T4 has been shown to up-regulate the proliferation of hair matrix keratinocytes and prolong the anagen phase, potentially by down-regulating TGF-beta2, an anagen-inhibitory growth factor 3. Additionally, both T3 and T4 modulate the expression of thyroid hormone-responsive keratins and stimulate melanin synthesis within hair follicles, further influencing hair growth and pigmentation 3.
Conclusion
The relationship between hypothyroidism and hair loss is well-documented, with thyroid hormones playing a pivotal role in hair follicle function. Hypothyroidism can lead to significant hair shedding, and a notable percentage of patients with diffuse hair loss have been found to have thyroid dysfunction. Understanding these connections is crucial for the effective diagnosis and management of hair loss associated with thyroid disorders. Further research is needed to fill the gaps in knowledge and improve treatment strategies for affected individuals.
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Most relevant research papers on this topic
Impact of Thyroid Dysfunction on Hair Disorders
Thyroid disorders have an underestimated prevalence and impact on hair loss, highlighting the need for more research to improve diagnosis and management of hair disorders.
Literature ReviewThyroid Functions in Patients with Diffuse Hair Loss
Abnormal thyroid functions are significant in a significant number of diffuse hair loss cases, making it mandatory to investigate them in all cases of diffuse hair loss in adult women.
Thyroid hormones directly alter human hair follicle functions: anagen prolongation and stimulation of both hair matrix keratinocyte proliferation and hair pigmentation.
Thyroid hormones directly affect human hair follicles, affecting hair growth, keratinocyte proliferation, and pigmentation.
In Vitro Study
Rigorous Journal
Highly CitedFemale Pattern Hair Loss and Androgen Excess: A Report From the Multidisciplinary Androgen Excess and PCOS Committee.
Female pattern hair loss (FPHL) should be referred to as "female pattern hair loss" and treated with minoxidil (5%), with additional treatments if necessary for severe hair loss or hyperandrogenism.
Systematic ReviewRigorous JournalHighly CitedAre you tired? Low Thyroid may be the Culprit: Part 1
Low thyroid hormone levels can cause low energy, weight gain, hair loss, and depression, but a proper diagnosis and treatment can help prevent these symptoms and improve overall health.
The Diagnosis and Treatment of Hair and Scalp Diseases.
Hair loss is a symptom caused by various genetic, endocrine, immune, and inflammatory processes, each requiring a different treatment approach.
Systematic ReviewHighly CitedHuman female hair follicles are a direct, nonclassical target for thyroid-stimulating hormone.
Female hair follicles are direct targets for nonclassical thyroid-stimulating hormone bioregulation, potentially affecting hair loss and promoting hair growth.
In Vitro StudyHighly CitedStudy of the Thyroid Profile of Patients with Alopecia
Alopecia areata shares an autoimmune background with thyroid diseases, and a multidisciplinary team is needed to improve outcomes and quality of life for patients.
Literature ReviewHow to diagnose hair loss.
A systematic approach to diagnosing hair loss involves history, clinical examination, laboratory tests, and scalp biopsy.
Systematic ReviewAlopecia areata
Alopecia areata is a nonscarring hair loss with spontaneous remissions and exacerbations, often associated with other conditions.
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