Hyperthyroidism and Skin Manifestations

This assignment delves into the relationship between hyperthyroidism and its impact on the skin. It examines specific skin conditions that can indicate hyperthyroidism, such as pretibial myxedema and alopecia. The document discusses diagnostic criteria for hyperthyroidism and explores the connection between these endocrine disorders and dermatological symptoms. Understanding this link is crucial for healthcare professionals to accurately diagnose and manage thyroid-related conditions.

Running head: HYPERTHYROIDISM AND ITS EFFECT ON SKIN 1
Hyperthyroidism and its effects on skin
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Hyperthyroidism and its effects on skin 2
Hyperthyroidism and its effects on skin
Introduction
Thyroid gland is an endocrine gland situated in the lower anterior part of neck. It has two lobes,
one on the right and one on the left side of trachea. They are joined in front of the trachea by
isthmus [1]. The isthmus is located just below the cricoid cartilage of trachea [5]. The gland
derives its name from its appearance resembling a shield, from the Greek word thyreos, which
means an oblong shield.
It secretes important hormones in the circulation, T3 and T4, triiodothyronine and thyroxine,
respectively, which play a very important role in metabolism throughout the body. It also
secretes a hormone called thyrocalcitonin or simply calcitonin [1].
The physiological role played by thyroid hormones is extremely important for each and every
body system. This explains the fact that the effects of dysfunction of the thyroid are seen in the
entire body including brain, heart, vascular system, skin, bones, reproductive system and
psychology. A developing embryo also needs a normal level of thyroid hormones for growth.
It is important to know this fact as it will help in diagnosis of thyroid dysfunction in a patient in
whom clinical examination of the thyroid gland appears normal. For example, knowledge of the
fact that a normal thyroid function is required for adequate brain function, will help in correct
diagnosis of hypothyroidism in a child whose parents just complain that he is slow in studies.
The thyroid gland may look absolutely normal in such patients
Thyroid stimulating hormone [TSH] secreted by pituitary gland located in brain regulates the
secretion of thyroid hormones through a feedback system

Hyperthyroidism and its effects on skin 3
Basic functions of thyroid hormones T3 and T4
T3 works at the nuclear level in virtually all the cells of the body. It binds to Thyroid hormone
nuclear receptors [TR]. It modifies the transcription of genes, which affects protein metabolism
and overall metabolic turnover. [2]
T4 is a precursor hormone of T3. It gets converted in T4 at intra- cellular level.
Thyroid dysfunction
Thyroid gland can develop structural diseases like swelling – goitre, nodules, abscess, cancer etc.
The function may or may not be affected in these cases.
In other cases the thyroid may be structurally normal but may function less causing inadequate
levels of T3 and T4 [Hypothyroidism] or may function more, causing excess levels of T3 and T4.
[Hyperthyroidism]
There could be combination of structural and functional defects
Hyperthyroidism can be due to a diffuse toxic goiter [Graves’ disease] or toxic multinodular
goiter or toxic adenoma.[8]
Manifestations
Many manifestations of hypo and hyperthyroidism are easy to understand as they reflect reduced
and excess metalobic activity respectively.

Hyperthyroidism and its effects on skin 4
A hypothyroid patient will have slow metabolism causing lack of appetite, weight gain,
bradycardia and excessive sleepiness. In contrast, a hyperthyroid patient will have opposite set of
complaints like excessive appetite, weight loss, tachycardia and insomnia.
These symptoms and signs are easy to understand on basis of either slowed or exaggerated
metabolism
The focus of the remaining article is now on details of the skin manifestations of
hyperthyroidism.
Dermatological manifestations of hyperthyroidism
There are some dermatological signs which can be explained on the basis of exaggerated
metabolism.
The sympathetic system is in a stimulated state in a patient of hyperthyroidism. It causes
vasodilatation in the peripheral circulation. Thus the skin may be warm and flushed. Excessive
sweating is seen often. [3]. The skin is often moist due to the sweat.
Diffuse hair loss is also seen but the severity of the hair loss does not correlate with the severity
of hyperthyroidism [3]. There is average one lac hair on the scalp and about a hundred are shed
daily. The alopecia seen in thyroid disorders is generally non scarring and non inflammatory in
nature. [4]
Onycholysis refers to separation of nail from its bed. Nails may also become softer. [2]
In a hyperthyroid state, there is acceleration of metabolism. Cortisol metabolism is also
accelerated, which leads to increased secretion of ACTH- adrenocorticotropic hormone through

Hyperthyroidism and its effects on skin 5
feedback mechanism, which can cause generalised hyperpigmentation in severe cases.
Hyperpigmentation can also be seen in hypothyroidism though it is more common in
hyperthyroidism.[12]
Jellinek’s sign refers to the hyperpigmentation of eyelids and is seen sometimes in
hyperthyroidism. [3]
Sometimes in a toxic nodular goiter, the overlying skin exhibits erythema. It is called Maroni
sign. It may or may not be associated with pruritus. [3]
Many patients with hyperthyroidism will have a large goiter. When such patient elevates both
arms, suffusion of the face and engorgement of the neck veins can be observed. This is called
Pemberton’s sign. It is seen more often with substernal goiters. [3, 6]
Autoimmune thyroid diseases are Graves’ disease and Hashimoto’s thyroiditis. In Graves’
disease there are Thyroid stimulating immunoglobulins [TSIs] in circulation. They stimulate
thyrotropin receptors. This causes hypertrophy of the thyroid gland with resultant increased
hormone production. Graves’ disease can occur by itself or it may be a part of generalised
autoimmune or connective tissue disorder. In such cases the patient may also have sysyemic
lupus erythematosus- SLE, Rheumatoid arthritis- RA, Sysyemic sclerosis, SSc or polyglandular
autoimmune syndrome. The dermatological manifestations of these diseases can then also be
present in the patient with Graves’ disease. [7]
Vitiligo and alopecia areata can be seen in such cases of hyperthyroidism due to an underlying
auto immune disorder. [3] Alopecia areata is seen as patchy non scarring type of alopecia. It is
commonly seen in scalp but can affect any hair bearing area.[9]

Hyperthyroidism and its effects on skin 6
Atopic dermatitis also sometimes associated with hyperthyroidism.[13]
Pretibial myxoedema and thyroid acropachy are specific skin manifestations seen in a case of
hyperthyroidism due to Graves’ disease.
Myxo is derived from Greek word myxa meaning mucous or slime [1].
Myxoedema refers to waxy and dry skin due to deposition of excess amounts of
glycosoaminoglycans in the dermis and is typically seen in hypothyroidism [1].
In contrast, pretibial myxoedema occurs in the shins of the legs in patients with Graves’ disease.
It may be present in dorsal surface of feet [13]. Occasionally it may be seen in upper limbs or
face [2]. The deposits are papular or plaque like in morphology. [1] It is non pitting by nature,
and is usually associated with redness and thickening of the overlying skin. Pain or pruritus are
generally absent [5]. The size can reach upto many centimetres [2].
Diffuse involvement of the skin is most common. Sometimes nodular lesions are also observed
[11].
The skin may resemble peel of an orange [5]. It is an infiltrative dermopathy. It may have a
violaceous or yellowish brown tinge. It is also called as thyroid dermopathy.
A severe form of thyroid dermopathy is elephantiasic form. As the name suggests, it is
accompanied by severe lymphedema. It can lead to disability and occasionally neuropathy
causing foot drop [11].
Though it is specific for Graves’ disease, it is not seen frequently. 0.5% - 4.3% of patients of
thyrotoxicosis and 15% of patients with Graves’ ophthalmopathy have pretibial myxoedema

Hyperthyroidism and its effects on skin 7
[10]. It is more common in ladies [10]. The chronological order of development is most
commonly thyrotoxicosis, followed by ophthalmopathy followed by pretibial myxoedema. In
rare cases it may be an isolated manifestation, without hyperthyroidism or ophthalmopathy. The
histopathological examination reveals mucin deposits. The deposits are seen in reticular dermis.
Hyaluronic acid is the chief component of the deposits [11]. The stains used for examination are
alcian blue and periodic acid Schiff [10]. With early identification and treatment of Graves’s
disease, the incidence is decreasing further. Goiter, ophthalmopathy and pretibial myxoedema
form classic triad of Graves’ disease [2]. It may rarely occur in patients with Hashimoto’s
thyroiditis. There is initially infiltration of the skin with lymphocytes. The lymphocytes secret
cytokines, which stimulate the fibroblasts to secret GSGs- glycosoaminoglycans [2]. Patients
with pretibial myxoedema exhibit high levels of circulating anti TSH receptor autoantibodies
[13]. Most often the diagnosis is clinical, especially in a patient with other typical manifestations
of Graves’ disease. An occasional patient may be euthyroid when the pretibial lesions are
present. In such cases punch biopsy of the skin may be used to confirm the diagnosis.
Thyroid acropachy refers to the swelling of hands and feet, clubbing of digits and new bone
formation in the periostium. As the name suggests it refers to the acral parts of the body,
meaning related to extremity or apex [1, 2].
Generalised itching and urticaria are also seen mainly in patients with Graves’ disease [2].
The combination of thyroid acropachy, pretibial myxoedema and ophthalmopathy in Graves’
disease is called as Diamond’s triad [3].
Key points

Hyperthyroidism and its effects on skin 8
Effect of many diseases of the endocrine system can be seen in skin and should be looked for
when a particular diagnosis is considered.
Hyperthyroidism also has many dermatological manifestations.
Some features like diffuse alopecia can be seen in hyper as well as hypothyroidism
Though myxoedema is a term used in relation to primary hypothyroidism, when it occurs in
pretibial location- pretibial myxoedema, it is specific for hyperthyroidism due to Graves’ disease.
In patients with connective tissue disorders and autoimmune diseases causing Graves’ disease,
many skin manifestations due to underlying disease like SLL or SSC can overlap on the features
of hyperthyroidism.
With early diagnosis and treatment of hyperthyroidism, the typical skin manifestations may not
be seen in many of the patients.

Hyperthyroidism and its effects on skin 9
References
1. Dorland’s .com. (2014). Dorland’s Illustrated Medical Dictionary, 30th edition,
Amsterdam: Elsevier.
2. Ross, D. (2017). Diagnosis of hyperthyroidism, Retrieved from<uptodate.com>.
3. Cox, N. H. & Niaimi, F. (2008). Endocrinology and the skin. Review article, Br J Hosp Med
(Lond). 69(9), 510-515.
4. Khopkar, U. (2001). An illustrated handbook of skin and sexually transmitted diseases, 3rd
edition, Bp.
5. WebMD LLC. (2017). Hyperthyroidism clinical presentation, Retrieved
from<http://emedicine.medscape.com/article/121865-clinical#b3>.
6. Filippis, D et al. (2014). Pemberton's sign: explained nearly 70 years later, J Clin
Endocrinol Metab., 99(6), 1949–1954. Retrieved
from<https://www.ncbi.nlm.nih.gov/pubmed/24646105>
7. Yeung, S.-C. J. (2017). Graves disease, WebMD LLC, Retrieved
from<http://emedicine.medscape.com/article/120619-overview>.
8. Lee, S. L. (2017). Hyperthyroidism, WebMD LLC, Retrieved
from<http://emedicine.medscape.com/article/121865-overview>.
9. Bolduc, C. (2016). Alopecia area at clinical presentation, WebMD LLC, Retrieved
from<http://emedicine.medscape.com/article/1069931-clinical>.

Hyperthyroidism and its effects on skin 10
10. Dhali, T. K., & CHahhar, M. (2014). Dermopathy—a diagnostic clue of hidden
hyperthyroidism, Dermatoendocrinol. 6(1), e981078, Retrieved
from<https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4580047/>
11. Heymann, W. R. (2017). Pretibial myxedema (thyroid dermopathy), Frontline Medical
Communications Inc., Retrieved
from<http://www.mdedge.com/clinicalendocrinologynews/dsm/1455/dermatology/pretibial-
myxedema-thyroid-dermopathy>
12. Singh, A. P. Cutaneous manifestations in thyroid disorders, Int J Med Sci., 2(1), 41–49.
Retrieved from<http://www.researchjournal.co.in/upload/assignments/2_41-45.pdf>
13. DEMİRkESEn, C. (2015). Skin manifestations of endocrine diseases, Turk Patoloji Derg,
31(Suppl), 145-154, Retrieved from<://www.turkjpath.org/pdf/pdf_TPD_1754.pdf>.