A retrospective study of thyroid structural abnormalities in alopecia patients

Evaluation of the relationship of digital phototrichogram findings of patients with diffuse hair loss with blood TSH, ferritin and vitamin B12 levels

OBJECTIVE

Telogen effluvium (TE) is a type of alopecia that is frequently seen in women. Among factors resulting in hair loss, many reasons such as endocrine diseases, nutrition disorders, stress, anemia, low ferritin levels, vitamin B12 deficiency, and thyroid diseases are found. A digital phototrichogram is one of the non-invasive methods of diagnosis in the evaluation of alopecia. In this study, it was aimed to compare biochemical parameters of female patients with diffuse hair loss with phototrichogram findings.

METHODS

108 female patients with diffuse hair loss were included in the study. Patients were divided into two groups: acute and chronic TE, and a hair pull test was applied. Total blood count, blood biochemistry, iron, iron binding capacity, ferritin, thyroid stimulating hormone (TSH), sT3, sT4, folic acid, and vitamin B12 levels were examined. The telogen/anagen ratios and hair densities of patients were determined with a phototrichogram.

RESULTS

The serum biochemical parameters (aspartate aminotransferase, alanine aminotransferase, urea, creatinine), TSH, sT3, sT4, and folic acid levels of patients were within normal limits. Telogen ratio, anagen ratio, hair density, number of shed hairs, family history, blood ferritin, TSH, and vitamin B12 levels were found to be similar between groups having acute and chronic TE. In our study, while mean anagen and telogen ratios with trichoscan were similar to literature data, no statistically significant correlation was determined between patients' ages and examined trichoscan findings (p>0.05). The hair pull test positivity of patients with chronic TE was higher compared to patients with acute TE (p<0.05). In patients with positive hair pull tests, the telogen ratio and hair density were found to be higher. In the group with <40 ng/mL ferritin level, the mean telogen ratio was detected to be significantly higher than the mean anagen ratio (p<0.05). No significant correlation was determined between vitamin B12 and TSH levels in patients and phototrichogram findings (p>0.05).

CONCLUSION

The findings of this study showed that ferritin has an important role in diffuse hair loss, and the phototrichogram method is an auxiliary method for the physician in the diagnosis of TE.

An Update on Alopecia and its Association With Thyroid Autoimmune Diseases

Alopecia is comorbid with several illnesses, including various autoimmune conditions such as thyroid disease. Leukocyte-mediated inflammation of hair follicles in alopecia was first described over a century ago. However, the high prevalence of the role of thyroid autoimmune disease in the pathogenesis of alopecia has only recently come to light, together with a strong association between the two. Therefore, this review focuses on articles published between 2011 and 2022 on alopecia's association with thyroid autoimmune disease, and the mechanism behind it. In addition, it highlights the link between alopecia and thyroid cancer, as patients with alopecia have increased risk of thyroid cancer. In conclusion, this comprehensive, focused, scoping review will serve as a reference highlighting recent information on alopecia, exploring its association with thyroid autoimmune diseases.

Comorbid Conditions Associated with Alopecia Areata: A Systematic Review and Meta-analysis

BACKGROUND

Alopecia areata (AA) is a complex autoimmune condition resulting in nonscarring hair loss. In recent years, many studies have provided new evidence on comorbid diseases present in patients with AA. However, some studies have conflicting results, and analyses conducting a comprehensive approach are lacking.

OBJECTIVE

The aim of our study was to provide an updated systematic review and meta-analysis of medical comorbidities associated with AA.

METHODS

We searched PubMed, Embase, and Web of Science for case-control, cross-sectional, and cohort studies investigating medical comorbidities in AA published from inception through 1 February 2023.

RESULTS

We screened 3428 abstracts and titles and reviewed 345 full text articles for eligibility. Ultimately, 102 studies were analyzed, comprising 680,823 patients with AA and 72,011,041 healthy controls. Almost all included studies (100 of 102 studies) were of satisfactory to high quality (Newcastle-Ottawa scale score ≥ 4). Among patients with AA, comorbidities with the highest odds ratios (OR) compared with healthy controls and data available from more than one study included vitamin D deficiency (OR 10.13, 95% CI 4.24-24.20), systemic lupus erythematous (OR 5.53, 95% CI 3.31-9.23), vitiligo (OR 5.30, 95% CI 1.86-15.10), metabolic syndrome (OR 5.03, 95% CI 4.18-6.06), and Hashimoto's thyroiditis (OR 4.31, 95% CI 2.51-7.40). AA may be a protective factor for certain disorders, for which the AA group had lower odds compared with healthy controls, such as irritable bowel syndrome (OR 0.38, 95% CI 0.14-0.99) and colorectal cancer (OR 0.61, 95% CI 0.42-0.89).

CONCLUSION

These findings corroborate and contextualize the risks across comorbidities for patients with AA. Further work should be done to identify the underlying pathophysiology and understand appropriate screening criteria.

Presence of Mast Cells and Mast Cell Degranulation in Scalp Biopsies of Telogen Effluvium

BACKGROUND

Telogen effluvium (TE) is a type of acquired, diffuse alopecia that occurs due to an abnormal shift of scalp hair follicles from anagen to telogen, leading to premature shedding of hair. Previous studies have suggested the existence of a neuroimmunologic "brain-hair follicle" axis, in which mast cells have been implicated as an important link between the nervous system and immunologic system.

OBJECTIVE

The current study sought to investigate the role of mast cell presence and mast cell degranulation in the pathogenesis of TE.

MATERIALS AND METHODS

Mast cells were counted using Giemsa and tryptase immunohistochemical stains in scalp biopsy specimens with the pathologic diagnosis of TE (TE, n = 10), alopecia areata (AA, n = 7), and androgenic alopecia (ANDRO, n = 9).

RESULTS

We found significant (P < 0.001) group-level differences between the mean mast cell counts per high-power fields for each type of alopecia studied. Tukey post hoc analysis showed the mean mast cell count for TE to be significantly larger than AA for both Giemsa (P = 0.002) and tryptase (P = 0.006); significantly larger than ANDRO for both Giemsa (P < 0.001) and tryptase (P < 0.001); and significantly larger when compared to normal scalp skin for both Giemsa (P < 0.001) and tryptase (P < 0.001). No significant difference of mean mast cell counts was observed for AA compared to ANDRO for Giemsa (P = 0.373) or tryptase (P = 0.598) stains.

CONCLUSION

Our findings suggest that mast cells could play a role in mediating stress-induced hair loss seen in TE.

Increased prevalence of thyroid disorders in patients with new onset alopecia areata

BACKGROUND

Several studies have revealed a high prevalence of thyroid disorders in patients with alopecia areata. The aim of the present study was to evaluate the frequency of thyroid function abnormalities and anti-thyroid auto-antibodies in patients with new onset alopecia areata on their first visit to a community dermatology clinic.

METHODS

The study included 78 patients with new onset alopecia areata who visited a community dermatology clinic between 2007 and 2011. Every patient underwent a complete medical history, physical examination and laboratory testing consisting of thyroid function tests (serum levels of free triiodothyronine, free thyroxine and thyroid stimulating hormone) and anti-thyroid auto-antibodies (thyroglobulin antibodies and thyroid peroxidase antibodies).

RESULTS

The 78 patients included 46 (59%) men and 32 (41%) women, with 1.44 male : female ratio and mean age of 32.7 +/- 3.09 years. Abnormal thyroid function and anti-thyroid auto-antibodies were detected in 19 (24%) patients. Of these, 12 (15%) patients were diagnosed with subclinical hypothyroidism, one (1%) with an overt hypothyroidism, one (1%) with an overt hyperthyroidism and four (5%) with euthyroid Hashimoto's thyroiditis.

CONCLUSION

The study revealed a significant association between alopecia areata and thyroid abnormalities. Screening for thyroid function and anti-thyroid auto-antibodies is advised in alopecia areata.

Women with alopecia exhibit a higher risk for thyroid cancer: a nationwide cohort study

BACKGROUND

Several studies have investigated the relationship between alopecia and prostate cancer. However, little information is available regarding the relationship between alopecia and the risk of cancers in women.

OBJECTIVE

The purpose of this study was to evaluate the possible association between alopecia and thyroid cancer among Taiwanese women.

METHODS

We used data from the National Health Insurance system of Taiwan. The alopecia cohort comprised 4534 women, and each woman was randomly frequency matched by age, index month, and index year with 4 women from the general population without alopecia. A Cox proportional hazard regression analysis with Bonferroni correction was conducted to estimate the effects of alopecia on the risk of thyroid cancer.

RESULTS

In women with alopecia, the overall risk for developing cancer was 22% higher than for subjects without alopecia, but the difference was not significant [hazard ratio (HR) = 1.22, 97.5% confidence interval (97.5% CI) = 0.87-1.70]. However, the risk for developing thyroid cancer among women with alopecia was significantly higher (HR = 2.39, 97.5% CI = 1.05-5.42). Further analyses determined that the alopecia group had a higher incidence of Graves' disease, but not Hashimoto thyroiditis.

CONCLUSION

Although alopecia did not significantly increase cancer risks in women, we found that Taiwanese women with alopecia had a higher risk of developing thyroid cancer that is unlikely to be related to underlying thyroid diseases.

MicroRNA/mRNA regulatory networks in the control of skin development and regeneration

Skin development, postnatal growth and regeneration are governed by complex and well-balanced programs of gene activation and silencing. The crosstalk between small non-coding microRNAs (miRNAs) and mRNAs is highly important for steadiness of signal transduction and transcriptional activities as well as for maintenance of homeostasis in many organs, including the skin. Recent data demonstrated that the expression of many genes, including cell type-specific master transcription regulators implicated in the control of skin development and homeostasis, is regulated by miRNAs. In addition, individual miRNAs could mediate the effects of these signaling pathways through being their downstream components. In turn, the expression of a major constituent of the miRNA processing machinery, Dicer, can be controlled by cell type-specific transcription factors, which form negative feedback loop mechanisms essential for the proper execution of cell differentiation- associated gene expression programs and cell-cell communications during normal skin development and regeneration. This review summarizes the available data on how miRNA/mRNA regulatory networks are involved in the control of skin development, epidermal homeostasis, hair cycle-associated tissue remodeling and pigmentation. Understanding of the fundamental mechanisms that govern skin development and regeneration will contribute to the development of new therapeutic approaches for many pathological skin conditions by using miRNA-based interventions.