Pretibial Myxedema

Pretibial myxedema is a rare skin condition that usually develops in people with Graves' disease. It causes thick, waxy patches of skin to form, most often on the shins and tops of the feet. The affected skin may look swollen, bumpy, or discolored.

This condition happens when certain substances build up in the skin tissue. Despite its name, pretibial myxedema is not caused by low thyroid function. It is actually linked to an overactive thyroid and the immune system attacking healthy tissue. The same antibodies that affect the thyroid gland in Graves' disease can also stimulate skin cells to produce excess material.

Only about 1 to 5 percent of people with Graves' disease develop pretibial myxedema. It typically appears after thyroid problems have been diagnosed, but sometimes shows up before or during treatment. While the condition can be uncomfortable or cosmetically concerning, it is not dangerous and does not affect overall health.

• Thick, waxy, or hardened patches of skin on the shins or feet
• Swelling in the lower legs and ankles
• Skin that appears shiny, red, or purple in color
• Raised bumps or nodules on the affected areas
• Skin texture that resembles orange peel
• Itching or discomfort in the affected areas
• Hair follicles that appear more prominent
• Tightness or stiffness in the skin

Some people experience mild symptoms that they barely notice. Others develop more visible changes that affect how they feel about their appearance. The condition typically does not cause pain, though some people report tenderness.

Pretibial myxedema develops when thyroid-stimulating immunoglobulins attack the skin. These are the same antibodies that cause Graves' disease by overstimulating the thyroid gland. The antibodies trigger cells in the skin to produce too much of a substance called glycosaminoglycan. This material accumulates in the tissue and causes the characteristic thick, swollen appearance.

Risk factors include having Graves' disease, a history of thyroid eye disease, and high levels of thyroid antibodies. Women are more likely to develop the condition than men. Smoking also increases the risk. The condition usually appears in people between ages 40 and 60, though it can occur at any age. Having the condition does not mean your thyroid disease is poorly controlled, as it can develop even when thyroid levels are normal.

Doctors diagnose pretibial myxedema by examining the affected skin and reviewing your medical history. If you have Graves' disease, the distinctive appearance of the skin changes often makes diagnosis straightforward. In some cases, a skin biopsy may be needed to confirm the diagnosis and rule out other conditions.

Blood tests help identify the underlying thyroid condition and measure antibody levels. Testing for thyroid-stimulating immunoglobulin, or TSI, can show elevated antibodies that drive both the thyroid disease and skin changes. Rite Aid offers TSI testing as an add-on to help monitor thyroid antibody levels. Regular testing helps track your immune system activity and guides treatment decisions.

• Topical corticosteroid creams to reduce inflammation and swelling
• Compression stockings to improve circulation and reduce fluid buildup
• Elevation of the legs to decrease swelling
• Keeping the skin moisturized to prevent cracking
• Treatment of the underlying Graves' disease with medication or radioactive iodine
• Smoking cessation to reduce inflammation
• Intralesional steroid injections for severe or resistant cases
• Pentoxifylline medication in some cases to improve blood flow

Most people see improvement with consistent treatment, though the condition may take months or years to resolve. Work closely with an endocrinologist and dermatologist for the best results. Treating the underlying thyroid condition is important but may not completely clear the skin changes.