Thyroid Dermopathy - An Overview

Introduction

Thyroid dermopathy is an autoimmune thyroid disease characterized by localized thickening of the skin in the pretibial area. It is related to ophthalmopathy and hyperthyroidism. It is a rare manifestation of Graves’ disease. It is one of the components of the classical triad goiter (neck inflammation due to thyroid gland enlargement), orbitopathy (inflammation of tissue around eyes), and pretibial myxedema (inflammation and think scaly plaques in lower limbs) of Grave’s disease. Thyroid dermopathy face occurrence is rare.

What Is Thyroid Dermopathy?

Thyroid dermopathy is also known as pretibial myxedema, localized myxedema, or infiltrative dermopathy. It is a rare disease and autoimmune. Localized skin lesions characterize it because of the deposition of hyaluronic acid. It involves the pretibial area, ankle, and dorsum of the foot, elbows, knees, upper back, and neck.

Pretibial myxedema occurs in five percent of Grave’s disease patients and 15 percent of patients with orbitopathy and Grave’s disease. Pretibial myxedema has decreased because of the early diagnosis of Grave’s disease and hypothyroidism. Antithyroid therapy is also given earlier to treat the condition effectively. The prevalence of pretibial myxedema with thyroid eye disease occurs in 0.15 per 10,000 persons.

Pretibia means the front side of the tibia, and myxedema implies swelling of the tissues under the skin. Anyone can be affected by pretibial myxedema. This may occur among individuals with the following conditions:

• Grave’s disease.
• Hyperthyroidism or hypothyroidism.
• Eye disease.
• Between the age group of 40 to 60.
• Women.

What Are the Types of Pretibial Myxedema?

Types of pretibial myxedema include the following:

• Diffuse: In this type, nonpitting edema of the leg can be seen. It is considered the most common type of pretibial myxedema.

• Plaque: Along with nonpitting edema, raised, thick, and scaly plaque can be observed on the skin.

• Nodular: Nodules can be observed with nonpitting edema.

• Elephantiasic: In this type, lymphatic fluid accumulation occurs underneath the skin and is considered the rarest form of pretibial myxedema.

What Are the Symptoms of Grave’s Dermopathy (Pretibial Myxedema)?

Pretibial myxedema is a skin condition developing among people with Grave’s disease. It is an autoimmune thyroid disease. Skin in Grave’s dermopathy appears as:

• Red or brown.
• Inflamed.
• Thickened.
• Orange peel texture.
• Itchy.
• Painful.

It usually affects both sides of the body in a symmetrical pattern. It sometimes involves only one side. Nine-six percent of thyroid dermopathy cases are of Grave’s ophthalmopathy, showing signs of bulging eyes, eye pain, and vision impairment. Sometimes, thyroid dermopathy is not diagnosed. Common symptoms of Grave’s disease are the following:

• Heat intolerance.
• Tremor.
• Tachycardia (fast heartbeats).
• Anxiety.
• Fatigue.
• Weight loss without reason (could be due to increased appetite).
• Frequent bowel movements.
• Goiter (swelling in front of the neck).
• Shortness of breath.

Pretibial myxedema shows a firm lump on the skin as an early symptom. Later, its size may change or merge with other lumps or nodules. The most commonly affected sites are as follows:

• The lower part of the legs.
• Feet.
• Shins.
• The face is affected by Grave’s disease or thyroid condition.

What Are the Causes of Thyroid Dermopathy?

The causes of thyroid dermopathy are as follows:

• It occurs because of autoimmune reactions as a part of Grave’s disease.
• The immune system targets cells that bind to TSH (thyroid-stimulating hormone). These cells are also present in the skin and are attacked by the immune system.
• T lymphocytes of the immune system enter the skin tissue and produce messenger proteins called cytokines. Cytokines, in turn, convey the message to cells to release too many glycosaminoglycans.

What Is the Progression of Thyroid Dermopathy?

It is generally seen in advanced conditions of thyroid diseases. It means that the underlying disease is not treated or undertreated. First, usually, hyperthyroidism develops, and later, Grave’s ophthalmopathy appears, and after this, Grave’s dermopathy develops. Thyroid acropachy (soft tissue swelling and clubbing of fingers and toes) develops among 20 percent of people with Grave’s dermopathy.

What Is the Pathogenesis of Thyroid Dermopathy?

Autoantibodies cross-react with connective tissue and muscle antigens against thyroid antigens and T lymphocytes. When TSH receptor antibodies bind to receptors in connective tissue, fibroblasts are stimulated to produce many glycosaminoglycans.

What Are the Clinical Features of Thyroid Dermopathy?

The thyroid dermopathy symptoms are the following:

• Non pitting edema.
• Induration of skin- peau d’orange appearance.
• Raised, hyperpigmented, violaceous papules.
• Plaques.
• Nodules.
• Polypoid or elephantiasic-type lesions.
• Hyperhidrosis(severe sweating).
• Stimulated sweat.

What Are the Sites Affected by Thyroid Dermopathy?

Localized lesions occur in the following areas:

• Pretibial - 99.4 percent.
• Pretibial and feet - 4.3 percent.
• Pretibial and upper extremities - 1.1 percent.
• Preradical aspect of arms.
• Upper back.
• Shoulders.
• Pinnae.
• Nose.
• Thigh and toes.

Prediction for the pretibial area is due to local trauma with factors (gravitational forces and differentiation by fibroblasts regarding site specification).

How to Diagnose Thyroid Dermopathy?

The following tests are done to diagnose thyroid dermopathy:

• Thyroid Function Test: To know the abnormality in the hormones (T3, T4, and TSH) of the thyroid gland is done.

• Histopathological Examination: Mucin deposition and separation of regular collagen bundles by mucin can be observed when tissue is stained with alcian blue and periodic acid Schiff. Compared to normal skin, fewer collagen fibers and edema can be observed. Sometimes, hyperkeratosis, acanthosis, and papillomatosis are observed.

• Ultrasonography: Used to document the thickness of pretibial myxedema (using 10-MHz ultrasonography).

How to Treat Thyroid Dermopathy?

Thyroid dermopathy treatment is as follows:

• Thyroid Disorders: Treating underlying thyroid problems does not solve skin problems in thyroid dermopathy.

• Corticosteroids: Intralesional or topical corticosteroids are used to treat the condition.

• Physical Therapy: Complete decompressive therapy can be given.

• Surgical: Surgical excision can be done to treat mild cases of thyroid dermopathy.

• Medications: Somatostatin analog and insulin analog are tried as newer therapies. These help decrease glycosaminoglycans by fibroblasts.

• Immunoglobulin Treatments: Antibodies are given intravenously for treatment.

• Plasmapheresis: A procedure that removes extra antibodies, abnormal proteins, or other harmful substances from the blood.

Studies have shown that 70 percent of mild thyroid dermopathy cases went into partial or complete remission without treatment, and 58 percent of severe cases went into partial or complete remission with treatment.

How Is Thyroid Dermopathy Prevented?

While it is impossible to avoid completely a condition called thyroid dermatopathy, individuals can get less chance of this disease through the following:

• Avoid the use of tobacco.
• Many situations could compromise the thyroid's performance, and one must receive appropriate treatment for those conditions.
• Stocking or compression stockings.

Conclusion:

Thyroid dermopathy is a rare autoimmune disease related to the endocrine system. Knowing about this disease in detail helps identify any symptoms that appear as soon as possible. As hormonally-related diseases are challenging to treat, in-depth knowledge helps in diagnosis and treatment. It allows one to seek the doctor's help as soon as possible, which leads to effective treatment. Timely help from the physician can effectively reverse the condition back to normal.