Thyroid disease and the skin

Chronic Venous Insufficiency With Emphasis on the Geriatric Population

The underpinning of Chronic Venous Insufficiency (CVI) is valvular dysfunction, which manifests on a spectrum depending on the severity of insufficiency and duration of the disease. The mainstay of treatment relies on compression therapy of a proper type and intensity. In older adults, special consideration must be taken during the patient encounter to account for age-related factors. This review discusses the clinical presentation, diagnosis, and mimicking of CVI, focusing mainly on older adults. The epidemiology, risk factors, disease burden, and grave complications -- such as thrombosis and ulceration, are reviewed. The physiological impacts of CVI are described, providing the background for treatment strategies, including non-invasive, medical, and surgical therapies. The findings show advanced age to be an important risk factor contributing to CVI and that other age-related factors add to the risk of severe complications. Clinical assessments combined with objective measurements that assess localized skin water using tissue dielectric constant values or whole limb assessments may aid in the differential diagnosis. Furthermore, understanding the mechanism of action of compression therapy, the mainstay of CVI treatment, and its physiological impacts, allows for its informed use in geriatric patients with increased risks of potential compression-related side effects.

A short review on the role of thyroxine in fast wound healing and tissue regeneration

Wound healing is a multiplex interaction process that involves extracellular matrix, blood vessels, proteases, cytokines, and chemokine. So far, a number of studies have been performed to understand the basis of the wound-healing process and multiple wound-healing products have been designed. However, significant morbidity and mortality incidents still occurred due to poor wound healing. Thus, there is a dire need to understand the effects of topical applications of various therapeutic options that lead to fast wound healing. Thyroxine is one great panacea for wound healing that has been vigorously mooted throughout the years but a conclusive result regarding its effectiveness is still not achieved. This review is intended to find a rational basis for its positive role in wound healing. To accomplish the objective, this review highlights the different aspects of thyroxine's role in wound healing like keratin synthesis, skin thickening, and pro-angiogenesis, the basis of controversy on its wound healing ability and its potential to be used as a wound healing agent. This study will be helpful for researchers and surgeons to assess the importance of thyroxine as a candidate to comprehensively research to develop a potent, effective, and affordable wound healing drug.

Clinicopathological insight into self-reported hair loss with no findings: How do we manage this enigmatic condition?

Patients who complain of hair loss without any supportive findings can be encountered in daily practice. To provide insight into this embarrassing condition, we retrospectively reviewed medical charts of eight cases with self-reported hair loss with no findings (SHLNOF). High frequency in middle aged women and concomitance of thyroid and gynecological problems were revealed. Four patients reported scalp dysesthesia/trichodynia. Two patients underwent scalp biopsy, both of which demonstrated increase in indeterminate hairs, suggesting mild hair miniaturization. Supportive medical consultation coupled with the presentation of clinical and trichoscopic images reassured the majority of the patients. These findings suggested that SHLNOF should not be disregarded simply as a misconception. A non-biased and diligent workup should be conducted to better manage this enigmatic condition.

Genome-wide DNA methylation analysis of Hashimoto's thyroiditis during pregnancy

Hashimoto's thyroiditis (HT) during pregnancy is usually accompanied by an elevation of thyroid‐stimulating hormone and a reduction of serum‐free thyroxine during gestation, which may lead to abortion, preterm delivery, and reduced intellectual function of the offspring. Epigenetic alterations may provide important insights into genetic–environmental interactions in HT. Here, we examined global DNA methylation patterns in patients with HT during pregnancy. DNA was extracted from 13 women with HT during pregnancy (HTDP) and eight healthy pregnant women as a control group. Genome‐wide methylation was detected with the use of an Illumina Human Methylation 850K Beadchip. A total of 652 differentially methylated positions (DMPs) and 27 differentially methylated regions (DMRs) were identified between the HTDP and control groups. GO analysis revealed that DMPs were significantly enriched in 540 GO terms, which included regulation of the differentiation of keratinocytes, T helper cell differentiation, and alpha‐beta T‐cell differentiation. Moreover, significant enrichment of KEGG pathways of the DMPs included mucin‐type O‐glycan biosynthesis, focal adhesion, and the insulin signaling pathway. The GO items associated with DMRs included muscle cell proliferation, response to biotic stimulus, anatomical structure formation involved in morphogenesis, and genes primarily involved in the FoxO signaling pathway. Finally, the DTNA gene was identified as the seed gene of functional epigenetic modules. In summary, the DNA methylation pattern of the HTDP group was distinct from that of the control group, and thus, changes in DNA methylation may influence the development of HT by regulation of the autoimmunity process.

Uncommon Site of Metastasis and Prolonged Survival in Patients with Anaplastic Thyroid Carcinoma: A Systematic Review of the Literature

Simple Summary

The therapeutic strategies employed for anaplastic thyroid cancer patients seems to be insufficient to prolong their survival, but some characteristics could predict a good prognosis, so that, starting from our experience we offer a systematic review of the literature to better understand anaplastic thyroid cancers behavior and their prognostic factors, in order to recognize and select the patients with the higher probability of better outcome even if metastatic. Moreover, we described an uncommon site of metastasis in order to improve scientific knowledge about this rare and highly aggressive pathology.

Abstract

Anaplastic thyroid carcinoma (ATC) is a very rare, highly aggressive malignant thyroid tumor with an overall survival from 3 to 5 months in most of the cases. Even the modern and intensive treatments seem not to be enough to provide a cure, also for the resectable ones, and the role of chemotherapy is still unclear but does not seem to prolong survival. Nevertheless, some patients survive longer and have a better outcome, even in the presence of metastasis, than what the literature reports. We present the case of a 64-year-old female affected by ATC, treated on February 2018 with surgery followed by chemoradiation. One year after surgery, the patient developed a subcutaneous recurrence that was radically resected and is still alive 29 months after the diagnosis. We propose a systematic review of the literature to deepen the knowledge of the prognostic factors of ATC with the aim to recognize and select the patients with a better outcome, even if metastatic, and to describe a very uncommon site of metastatization.

Topical L-thyroxine: The Cinderella among hormones waiting to dance on the floor of dermatological therapy?

Topical hormone therapy with natural or synthetic ligands of nuclear hormone receptors such as glucocorticoids, vitamin D analogues and retinoids has a long and highly successful tradition in dermatology. Yet the dermatological potential of thyroid hormone receptor (TR) agonists has been widely ignored, despite abundant clinical, cell and molecular biology, mouse in vivo, and human skin and hair follicle organ culture data documenting a role of TR-mediated signalling in skin physiology and pathology. Here, we review this evidence, with emphasis on wound healing and hair growth, and specifically highlight the therapeutic potential of repurposing topical L-thyroxine (T4) for selected applications in future dermatological therapy. We underscore the known systemic safety and efficacy profile of T4 in clinical medicine, and the well-documented impact of thyroid hormones on, for example, human epidermal and hair follicle physiology, hair follicle epithelial stem cells and pigmentation, keratin expression, mitochondrial energy metabolism and wound healing. On this background, we argue that short-term topical T4 treatment deserves careful further preclinical and clinical exploration for repurposing as a low-cost, effective and widely available dermatotherapeutic, namely in the management of skin ulcers and telogen effluvium, and that its predictable adverse effects are well-manageable.

The Thyroid Hormone Inactivator Enzyme, Type 3 Deiodinase, Is Essential for Coordination of Keratinocyte Growth and Differentiation

Background: Thyroid hormones (THs) are key regulators of development, tissue differentiation, and maintenance of metabolic balance in virtually every cell of the body. Accordingly, severe alteration of TH action during fetal life leads to permanent deficits in humans. The skin is among the few adult tissues expressing the oncofetal protein type 3 deiodinase (D3), the TH inactivating enzyme. Here, we demonstrate that D3 is dynamically regulated during epidermal ontogenesis. Methods: To investigate the function of D3 in a postdevelopmental context, we used a mouse model of conditional epidermal-specific D3 depletion. Loss of D3 resulted in tissue hypoplasia and enhanced epidermal differentiation in a cell-autonomous manner. Results: Accordingly, wound healing repair and hair follicle cycle were altered in the D3-depleted epidermis. Further, in vitro ablation of D3 in primary culture of keratinocytes indicated that various markers of stratified epithelial layers were upregulated, thereby confirming the pro-differentiative action of D3 depletion and the consequent increased intracellular triiodothyronine levels. Notably, loss of D3 reduced the clearance of systemic TH in vivo, thereby demonstrating the critical requirement for epidermal D3 in the maintenance of TH homeostasis. Conclusion: In conclusion, our results show that the D3 enzyme is a key TH-signaling component in the skin, thereby providing a striking example of a physiological context for deiodinase-mediated TH metabolism, as well as a rationale for therapeutic manipulation of deiodinases in pathophysiological contexts.

Thyroid diseases and skin autoimmunity

The skin is the largest organ of the body, at the boundary with the outside environment. Primarily, it provides a physical and chemical barrier against external insults, but it can act also as immune organ because it contains a whole host of immune-competent cells of both the innate and the adaptive immune systems, which cooperate in eliminating invading pathogens following tissue injury. On the other hand, improper skin immune responses lead to autoimmune skin diseases (AISD), such as pemphigus, bullous pemphigoid, vitiligo, and alopecia. Although the interplay among genetic, epigenetic, and environmental factors has been shown to play a major role in AISD etiology and progression, the molecular mechanisms underlying disease development are far from being fully elucidated. In this context, epidemiological studies aimed at defining the association of different AISD with other autoimmune pathologies revealed possible shared molecular mechanism(s) responsible for disease progression. In particular, over the last decades, a number of reports have highlighted a significant association between thyroid diseases (TD), mainly autoimmune ones (AITD), and AISD. Here, we will recapitulate the epidemiology, clinical manifestations, and pathogenesis of the main AISD, and we will summarize the epidemiological evidence showing the associations with TD as well as possible molecular mechanism(s) underlying TD and AISD pathological manifestations.

General hyperpigmentation induced by Grave's disease: A case report

RATIONALE

Hyperpigmentation is a common skin disease. However, there are few reported cases of Grave's disease with diffuse hyperpigmentation. We hereby described a rare case with diffuse hyperpigmentation induced by Grave's disease.

PATIENT CONCERNS

A 42-year-old Chinese woman with accumulated general pigmentation of skin was admitted to our hospital in October 2017. On examination, hyperpigmentation was observed throughout the whole body, especially on the extremities and the face.

DIAGNOSES

The patient has elevated levels of serum free thyroxine (FT4), free triiodothyronine (FT3), reduced levels of thyroid-stimulating hormone (TSH) and positive anti-TSH receptor antibody (TRAb). She presented with grade I goiter and a diffusely increased thyroid uptake to 18.5% in thyroid scan. Histopathological examination demonstrated melanin pigmentation in the pigmented skin area. The patient was diagnosed with hyperpigmentation induced by Grave's disease.

INTERVENTIONS

The patient was treated with oral methimazole (15 mg/day) for thyroid dysfunction and beta blocker for symptom control.

OUTCOMES

After a period of treatment with methimazole and beta blocker, symptoms of hyperthyroidism ameliorated and hyperpigmentation abated.

LESSONS

Our studies proposed that in this case the diffuse hyperpigmentation in Grave's disease was caused by elevated adrenocorticotropic hormone (ACTH) as well as anti- TSH receptor stimulating antibody instead of enhanced capillary fragility. Other potential mechanisms for skin pigmentation in hyperthyroidism still need further exploration.

Non-Desmoglein Antibodies in Patients With Pemphigus Vulgaris

Pemphigus vulgaris (PV) is a potentially life-threatening mucocutaneous autoimmune blistering disease. Patients develop non-healing erosions and blisters due to cell–cell detachment of keratinocytes (acantholysis), with subsequent suprabasal intraepidermal splitting. Identified almost 30 years ago, desmoglein-3 (Dsg3), a Ca²⁺-dependent cell adhesion molecule belonging to the cadherin family, has been considered the “primary” autoantigen in PV. Proteomic studies have identified numerous autoantibodies in patients with PV that have known roles in the physiology and cell adhesion of keratinocytes. Antibodies to these autoantibodies include desmocollins 1 and 3, several muscarinic and nicotinic acetylcholine receptor subtypes, mitochondrial proteins, human leukocyte antigen molecules, thyroid peroxidase, and hSPCA1—the Ca²⁺/Mn²⁺-ATPase encoded by ATP2C1, which is mutated in Hailey–Hailey disease. Several studies have identified direct pathogenic roles of these proteins, or synergistic roles when combined with Dsg3. We review the role of these direct and indirect mechanisms of non-desmoglein autoantibodies in the pathogenesis of PV.

E-cadherin roles in animal biology: A perspective on thyroid hormone-influence

The establishment, remodeling and maintenance of tissular architecture during animal development, and even across juvenile to adult life, are deeply regulated by a delicate interplay of extracellular signals, cell membrane receptors and intracellular signal messengers. It is well known that cell adhesion molecules (cell-cell and cell-extracellular matrix) play a critical role in these processes. Particularly, adherens junctions (AJs) mediated by E-cadherin and catenins determine cell-cell contact survival and epithelia function. Consequently, this review seeks to encompass the complex and prolific knowledge about E-cadherin roles during physiological and pathological states, particularly focusing on the influence exerted by the thyroid hormone (TH).

Anaplastic thyroid carcinoma with diffuse thoracic skin metastasis: A case report

Anaplastic thyroid carcinoma is a significantly fatal endocrine neoplasm, with an average survival time of 4–12 months following diagnosis. The present study reports the case of a 57-year-old male patient who presented to the Bağcılar Training and Research Hospital (Istanbul, Turkey) due to swelling in the neck and difficulty swallowing. The jugular mass biopsy results were consistent with a diagnosis of anaplastic thyroid cancer. The patient was regarded to have advanced-stage subcarinal, paratracheal, aortopulmonary, trancheobronchial and mediastinal lymphadenopathies and exhibited a good prognosis following chemotherapy. However, the patient succumbed one month later due to the emergence of diffuse skin lesions. The histopathological and immunohistochemical assessment of the skin biopsy displayed the characteristics of the underlying thyroid carcinoma.

A hand surgeon's guide to common onychodystrophies

The human fingernail contributes to the precise dexterity of the fingers, enhances sensibility, allows manipulation of fine objects, and shields the fingertip from traumatic injury. Nail abnormalities are a common incidental finding in the course of a hand surgeon's daily practice. These abnormalities may be clues to systemic, dermatologic, traumatic, and infectious processes that would benefit from further evaluation and treatment. The purpose of this review is to discuss common nail dystrophies and their related diagnoses.

Cicatricial changes in ocular pemphigus

PURPOSE

To describe the clinical characteristics of ocular involvement in patients with pemphigus at an ophthalmological referral center.

METHODS

A retrospective review was conducted on patients with the immunopathological diagnosis of pemphigus examined between 1 January 2000 and 1 April 2010. Uncorrected distance visual acuity (UDVA), best corrected distance visual acuity (BCVA), ocular symptoms, and ocular surface inflammatory and scarring changes were assessed.

RESULTS

A total of 15 patients were identified, with a mean age of 68.27 ± 14.35 years, and 80% (n=12) were female. Extraocular involvement was reported in one patient. All of the eyes showed cicatricial changes in the conjunctiva. In all, 6 eyes (20%) were classified as stage I; 12 eyes (40%) as stage II; 10 eyes (33%) as stage III; and 2 eyes (7%) as stage IV. A statistically significant association was found between BCVA and the severity of ocular involvement. The mean BCVA logMAR was 1.66 (20/914), with a range from logMAR 0 (20/20) to logMAR 4 (NLP). Other ocular diseases were found in 8 (53.3%), systemic diseases in 10 (66.7%), and the use of pemphigus-inducing drugs in 10 patients (66.7%).

CONCLUSIONS

The present report represents the largest series of ocular involvement in pemphigus confirmed by immunopathology. The clinical manifestations varied from conjunctival hyperemia to corneal scarring and perforation. There was a strong association between scarring changes and low BCVA. Ocular and systemic diseases as well as the use of pemphigus-inducing drugs may predispose to ocular cicatricial changes observed in this series.

An Intimate Relationship between Thyroid Hormone and Skin: Regulation of Gene Expression

Skin is the largest organ of the human body and plays a key role in protecting the individual from external insults. The barrier function of the skin is performed primarily by the epidermis, a self-renewing stratified squamous epithelium composed of cells that undergo a well-characterized and finely tuned process of terminal differentiation. By binding to their receptors thyroid hormones (TH) regulate epidermal cell proliferation, differentiation, and homeostasis. Thyroid dysfunction has multiple classical manifestations at skin level. Several TH-responsive genes, as well as genes critical for TH metabolism and action, are expressed at epidermal level. The role of TH in skin is still controversial, although it is generally recognized that TH signaling is central for skin physiology and homeostasis. Here we review the data on the epidermis and its function in relation to TH metabolism and regulation of gene expression. An understanding of the cellular and molecular basis of TH action in epidermal cells may lead to the identification of putative therapeutical targets for treatment of skin disorders.

Madarosis: a marker of many maladies

Madarosis is a terminology that refers to loss of eyebrows or eyelashes. This clinical sign occurs in various diseases ranging from local dermatological disorders to complex systemic diseases. Madarosis can be scarring or non-scarring depending upon the etiology. Appropriate diagnosis is essential for management. Follicular unit transplantation has been found to be a useful method of treating scarring madarosis and the procedure relevant to eyebrow and eyelash reconstruction has been discussed. A useful clinical approach to madarosis has also been included for bedside diagnosis. The literature search was conducted with Pubmed, Medline, and Google scholar using the keywords madarosis, eyebrow loss, and eyelash loss for articles from 1960 to September 2011. Relevant material was also searched in textbooks and used wherever appropriate.

The deiodinases and the control of intracellular thyroid hormone signaling during cellular differentiation

Background

Thyroid hormone influences gene expression in virtually all vertebrates. Its action is initiated by the activation of T4 to T3, an outer ring deiodination reaction that is catalyzed by the type 1 or the type 2 iodothyronine selenodeiodinases (D1 or D2). Inactivation of T4 and T3 occurs via inner ring deiodination catalyzed by the type 3 iodothyronine selenodeiodinases (D3). The T4 concentration is generally quite stable in human plasma, with T3 levels also remaining constant. Deiodinase actions are tightly regulated in both pre- and post-natal life when they are required to make local adjustments of intracellular T3 concentrations in a precise spatio- and temporal manner. Although all the signals governing the dynamic expression of deiodinases in specific cell types are not known, many important regulatory factors have been deciphered.

Scope of review

This review provides striking examples from the recent literature illustrating how the expression of D2 and D3 is finely tuned during maturation of different organs, and how their action play a critical role in different settings to control intracellular T3 availability.

Major conclusions

Emerging evidence indicates that in various cell contexts, D2 and D3 are expressed in a dynamic balance, in which the expression of one enzyme is coordinately regulated with that of the other to tightly control intracellular T3 levels commensurate with cell requirements at that time.

General significance

Deiodinases control TH action in a precise spatio-temporal fashion thereby providing a novel mechanism for the local paracrine and autocrine regulation of TH action. This remarkable tissue-specific regulation of intracellular thyroid status remains hidden due to the maintenance of constant circulating TH concentrations by the hypothalamic–pituitary–thyroid axis. This article is part of a Special Issue entitled Thyroid hormone signalling.

Hypothyroidism improves random-pattern skin flap survival in rats

BACKGROUND

The protective effect of hypothyroidism against ischemic or toxic conditions has been shown in various tissues. We investigated the effect of propylthiouracil (PTU)/methimazole (MMI)-induced hypothyroidism and acute local effect of MMI on the outcome of lethal ischemia in random-pattern skin flaps.

MATERIALS AND METHODS

Dorsal flaps with caudal pedicles were elevated at midline and flap survival was measured at the seventh day after surgery. The first group, as control, received 1 mL of 0.9% saline solution in the flap before flap elevation. In groups 2 and 3, hypothyroidism was induced by administration of either PTU 0.05% or MMI 0.04% in drinking water. The next four groups received local injections of MMI (10, 20, 50, or 100 μg/flap) before flap elevation. Local PTU injection was ignored due to insolubility of the agent.

RESULTS

Hypothyroidism was induced in chronic PTU- and MMI-treated groups, and animals in these groups showed significant increase in their flap survival, compared to control euthyroid rats (79.47% ± 10.49% and 75.48% ± 12.93% versus 52.26% ± 5.75%, respectively, P < 0.01). Acute local treatment of skin flaps with MMI failed to significantly affect the flap survival.

CONCLUSION

This study demonstrates for the first time that hypothyroidism improves survival of random-pattern skin flaps in rats.

Skin signs of systemic diseases

The skin should not be considered as an isolated organ but rather as a definite functioning system that communicates with the internal environment. Skin signs of systemic diseases occur frequently and sometimes feature the first symptoms of an internal disease; furthermore, these manifestations may be the sole expressions of otherwise asymptomatic systemic disorders. A number of dermatologic signs, symptoms, and disorders can be invaluable as markers of systemic disease. Although a plethora of specialized modern diagnostic tests are available, the skin still remains the only organ of the body that is immediately and completely accessible to direct clinical examination. This contribution reviews the skin signs of systemic diseases. The description of the clinical features of skin lesions observed in several internal diseases will be useful to general physicians, internists, and dermatologists in the diagnosis of a systemic disease.

TSH receptor and thyroid-specific gene expression in human skin

Experimental evidence suggests that in autoimmune thyroid diseases (AITDs) the skin is a target of autoantibodies against thyroid-specific antigens; however, the role of these autoantibodies in skin alterations remains unclear. To gain insight into the function of nominally thyroid-specific genes in skin, we analyzed the expression of thyroid-stimulating hormone-receptor (TSH-R), thyroglobulin (Tg), sodium iodide symporter (NIS), and thyroperoxidase (TPO) genes in normal human skin biopsies and cultured primary keratinocytes and dermal fibroblasts. The results revealed the presence of all the transcripts in skin biopsies. However, in keratinocytes and fibroblasts, only TSH-R messenger RNA was always detected. Western blot and immunohistochemical analyses of skin specimens confirmed the presence of TSH-R protein in keratinocytes and fibroblasts. Moreover, TSH treatment induced the proliferation of cultured keratinocytes and fibroblasts and increased keratinocyte intracellular cAMP. Finally, affinity-purified IgGs from serum of patients affected by Graves' disease, but not by chronic lymphocytic thyroiditis, stimulated cAMP accumulation in cultured keratinocytes, as well as their proliferation. In conclusion, the expression of thyroid-specific genes in cultured keratinocytes and fibroblasts and the mitogenic effects of TSH and IgGs on these cells support the concept that autoantibodies against thyroid-specific antigens may contribute to cutaneous symptoms in AITDs.

Skin findings in thyroid diseases

BACKGROUND

In cases of thyroid diseases, many of the symptoms arise on the skin. In this study, we aimed to detect and compare the skin findings and accompanying dermatoses of patients with thyroid diseases.

MATERIALS AND METHODS

220 patients with thyroid diseases, who did not have any medical cure, and 90 healthy individuals as a control group attended our study. All of the cases were examined, and the skin findings and/or dermatoses were recorded. The skin findings in the patients and the control group were compared statistically.

RESULTS

Among 220 cases, in 125 (56.8%) skin findings were detected. The most frequently observed skin findings were chronic urticaria (6.8%), vitiligo (6.8%), diffuse alopecia (6%), acne vulgaris (5%) and acne rosacea (3.6%). No significant difference was detected statistically between the patients and control group in terms of skin findings. When compared for the presence of each dermatosis, chronic urticaria, vitiligo and pruritus were found to be significantly higher in the patient group with thyroid diseases than in the control group. In terms of the presence of skin findings, no statistical difference was detected between autoimmune hyperthyroidism and non-autoimmune hyperthyroidism, between autoimmune hypothyroidism and non-autoimmune hypothyroidism, or between autoimmune euthyroidism and non-autoimmune euthyroidism. Chronic urticaria, vitiligo, and diffuse alopecia were found to be significantly higher in patients with autoimmune thyroid diseases than in the control group. Vitiligo and diffuse alopecia were found to be higher in autoimmune hyperthyroidism patients than in the control group. Vitiligo was found to be significantly higher in autoimmune hypothyroidism patients than in the control group.

CONCLUSION

To our knowledge, no report investigating the skin findings among thyroid diseases exists in literature. We believe this study would provide data for further studies.

Human female hair follicles are a direct, nonclassical target for thyroid-stimulating hormone

Pituitary thyroid-stimulating hormone (TSH) regulates thyroid hormone synthesis via receptors (TSH-R) expressed on thyroid epithelial cells. As the hair follicle (HF) is uniquely hormone-sensitive and, hypothyroidism with its associated, increased TSH serum levels clinically can lead to hair loss, we asked whether human HFs are a direct target for TSH. Here, we report that normal human scalp skin and microdissected human HFs express TSH-R mRNA. TSH-R-like immunoreactivity is limited to the mesenchymal skin compartments in situ. TSH may alter HF mesenchymal functions, as it upregulates alpha-smooth muscle actin expression in HF fibroblasts. TSH-R stimulation by its natural ligand in organ culture changes the expression of several genes of human scalp HFs (for example keratin K5), upregulates the transcription of classical TSH target genes and enhances cAMP production. Although the functional role of TSH in human HF biology awaits further dissection, these findings document that intracutaneous TSH-Rs are fully functional in situ and that HFs of female individuals are direct targets for nonclassical, extrathyroidal TSH bioregulation. This suggests that organ-cultured scalp HFs provide an instructive and physiologically relevant human model for exploring nonclassical functions of TSH, in and beyond the skin.

Dermatologic aspects of thyroid disease

Thyroid disorders commonly have dermatologic manifestations. The purpose of the present chapter is to review and emphasize potential clinical dermatologic findings that can occur with Graves' disease, hypothyroidism and thyroid cancer. In autoimmune diseases such as Graves' disease and Hashimoto's thyroiditis the skin manifestations may be related to either thyroid hormone levels themselves or to the associated T and/or B cell abnormalities. Thyroid cancer may be associated with various syndromes that could have significant skin manifestations.

Dermatologic manifestations of hypopituitarism

Hypopituitarism is characterized by diminished or absent secretion of one or more pituitary hormones. The clinical features of hypopituitarism vary depending on age, rapidity of onset, hormones involved, and degree of deficiency. Dermatologic signs of hypopituitarism may involve alterations in pigmentation, the epidermal and dermal skin structures, and the pilosebaceous unit. We describe the causes and presentation of hypopituitarism with an emphasis on its dermatologic manifestations.

Cutaneous manifestations of endocrine-metabolic disease and nutritional deficiency in the elderly

This article explores cutaneous manifestations of endocrine-metabolic disease and nutritional deficiency in the elderly. Topics covered include the following: diabetes mellitus, thyroid disorders, adrenal dysfunction, pituitary disorders, parathyroid disease, nutritional deficiencies, menopause, and HIV.