Psoriatic arthritis and hypothyroidism are both autoimmune disorders. While one does not cause the other, they are linked, suggesting that having one means you’re more likely to have the other.
Psoriatic arthritis (PsA) is an inflammatory form of arthritis that causes swollen, stiff, and painful joints. Meanwhile, hypothyroidism affects your thyroid, which is the butterfly-shaped gland in your neck that produces hormones. When you have hypothyroidism, this gland doesn’t make enough thyroid hormones.
PsA and psoriasis are also autoimmune disorders. These conditions cause your immune system to attack healthy joints and skin. In hypothyroidism, your immune system’s target is the thyroid gland.
Read on to learn how these two conditions are related.
Psoriasis isn’t a symptom of hypothyroidism. But if you have psoriasis or PsA, you’re more likely to have at least one other autoimmune disease,
- rheumatoid arthritis
- Crohn’s disease
- ulcerative colitis
- hypothyroidism
- diabetes
- vitiligo
In autoimmune thyroid disease, the immune system makes proteins called antibodies that damage the thyroid gland.
People with PsA and psoriasis are more likely to test positive for thyroid antibodies than people without these conditions. In a 2020 study, about
Thyroid hormones act on many different parts of your body, including your skin. These hormones may trigger psoriasis or make symptoms worse.
Specifically, thyroid hormones increase the level of growth factors. These growth factors cause the skin cells that form scaly psoriasis plaques to multiply. Too much thyroid hormone production makes psoriasis symptoms worse.
Hypothyroidism isn’t a skin disease. But like psoriasis and PsA, it can affect your skin.
Skin symptoms of hypothyroidism include:
- dry, scaly skin that cracks
- swelling of your hands, face, and eyelids, which are symptoms of severe hypothyroidism (myxedema)
- pale or yellow skin
Generalized myxedema is a complication of severe hypothyroidism. It causes:
- waxy, doughy-looking skin
- swelling of the lips, eyelids, and tongue
- dryness
Doctors treat myxedema rash with corticosteroid creams and injections.
Pretibial myxedema (PTM) is a red or discolored, swollen, and thick skin rash. It’s a rare symptom of thyroid conditions, including Hashimoto thyroiditis and Graves’ disease.
This rash forms when hyaluronic acid, a natural lubricant your body makes, builds up under your skin. The affected skin becomes thick and has the texture of an orange peel.
PTM most often appears on the shins or the tops of the feet. It also can form on areas like your:
- knees
- shoulders
- elbows
- upper back
- ears
- nose
- neck
If you have symptoms of PsA or Hashimoto thyroiditis that don’t go away, it’s a good idea to speak with a doctor.
Symptoms of PsA to look out for
- painful, swollen fingers and toes
- stiffness, swelling, and pain in one or more joints
- reduced range of motion in your joints
- nail changes, such as a nail that has pits or separates from the nail bed
- red or discolored, scaly patches of skin
- itchy or burning skin
- lower back pain
Hashimoto thyroiditis symptoms
- swelling in your neck, called a goiter
- unusual tiredness
- weight gain
- muscle weakness
- increased sensitivity to cold
- dry skin and hair
- brittle, splitting nails
Your doctor will ask about your symptoms and medical history. They may order blood tests to check your thyroid hormone levels, as well as imaging tests to check your joints for damage.
PsA and hypothyroidism are both types of autoimmune disorders. When you have PsA or psoriasis, you’re also more likely to have thyroid disease.
If you have symptoms of PsA or hypothyroidism, contact your doctor for an exam. Treatments can slow the joint damage and skin plaques of PsA, as well as restore normal hormone levels in hypothyroidism.