Thyroid function and Skin

When most people, even most doctors, think of hypothyroidism, they think of the symptoms of myxedema. Myxedema was the original term for hypothyroidism, first described by William Ord in 1878. This extreme hypothyroidism causes swelling and such a slowed metabolism that you can go into a coma. The swelling is usually in the face and the front of the lower leg, called pretibial swelling. More women suffer from it than men. Myxedema is rare in the Western world, mainly because a doctor figures out that thyroid levels are dangerously low when the face is swollen. They were trained to look for this symptom. Unfortunately, low thyroid function causes many other physiological problems and skin conditions. The term myxedema isn't used much anymore, but if we look at what caused the state of myxedema, we immediately understand thyroid function severely impacts the skin.In extreme cases, the skin will look like it had too many dermal filler injections because they are the same. Dermal fillers, injected into your lips and cheeks, are made from hyaluronic acid. This popular substance is also injected into cheeks and joints and used in hair and skin products. Hyaluronic acid is a polysaccharide. It occurs naturally in human tissues. It is everywhere nowadays because it can hold up to 1000 times its weight in water. Hyaluronic acid makes researchers think—hydration, smooth skin, and more space between vertebrae! However, hyaluronic acid is a glycosaminoglycan that, although it can hold a ton of water, can also pull a ton of water out of the tissue. Instead of rehydrating, it ends up causing dryness.

Glycosaminoglycans, or GAGs, do essential things in our bodies. Heparin is a GAG, and it is an anticoagulant. But too much of it causes GAG storage disorders, accumulating in various tissues to cause joint stiffness, deafness, knock knees, damaging heart valves, and pleural effusion. Gags serve as biological response modifiers and are involved in cytokine signaling in response to viruses, bacteria, and antibodies. If you hurt yourself, GAGs come to seal the area. Think of the kind of inflammation they can cause if they build up in tissues where they are not needed. That is precisely what happens with hypothyroidism. All liquid circulation is stuck, so swelling occurs. The skin feels firm and swollen. It looks pale, dry, and waxy. It is what classical osteopaths call tissue congestion. You see it in the faces of photos of people with severe hypothyroidism over a hundred years ago. Unfortunately, this kind of glycosaminoglycan deposit can happen in any tissue— tongue, eyelids, joints, around your nerves. It's what causes carpal tunnel syndrome.

Thyroid hormone influences skin and connective tissue in so many ways. Thyroid hormones also have a significant influence on hair. Hair has thyroid hormone receptors. Thyroid hormone receptors are found in keratinocytes, skin fibroblasts, hair arrector pili muscle cells, smooth muscle cells, sebaceous glands, vascular endothelial cells, Schwann's cells, and in cells making hair follicles. Hypothyroidism can cause dry, brittle hair, alopecia, and thinning hair. Nails are affected and can be thick and brittle or grow very slowly. Thyroid hormone regulates epidermal growth, both regeneration and homeostasis. In hypothyroidism, skin is often rough and scaly, especially on the hands and feet, where physiological energy and nutrition arrive last.

One of my patients recently remarked that the skin on the insides of her fingers was no longer dry and sore. The soles of the feet are often dry and cracked. The skin will be thinning or thickening with hyperkeratosis. Hypothyroidism can damage even hearing because if T3 doesn't get to cochlear cells, you can get lesions on the inner ear. Without T3 hormone, skin cells can't synthesize the lipids that form a protective barrier on the skin to keep it moisturized. Which means dry, cracking, and wrinkly skin. This is why I often see low vitamin D levels in hypothyroidism.

Many people who don't eat animal fat don't get vitamin D3 from their food. But they are lying in the sun, expecting the lipids on their skin to make D3 from supplements, fortified grains, and plant milk, yet their skin doesn't have enough dermal lipids in the form of keratinocytes due to low T3. They won't be making vitamin D their body can use. Not enough thyroid hormones reach skin cells, which can cause non-pitting edema. That is the hard swelling that pushes at the skin so much that it hurts all over. This is the GAG accumulating in skin tissue. Remember that hyaluronic acid holds 1000 times its weight in water. Areas of the body that don't have much muscle tissue can swell, like ankles, feet, hands, face, and eyelids. In middle-aged women, I often see swelling in the area at the back of the neck where the cervical spine meets the dorsal spine, often called dowager's hump or, in Italian, buffalo hump. We are told it's caused by sitting long hours at the computer or texting on the phone, but every dowager's hump I've seen was caused by hypothyroidism.

Hypothyroid skin often looks pale or yellow. Carotene can build up in the skin, tingling the hands, feet, and skin around the eyes with yellow. With low T3, sebaceous glands secrete less sebum, so there is less sweating. Because T3 regulates the good lipophilic flora, lack of it can cause candida buildup in tissue with hair follicles. This buildup will eventually cause acne and infection in the hair follicles. Because of the hyaluronic acid accumulation with low T3, mucin can collect in organ tissue like the tongue, heart muscle, and lungs. Lymphatic drainage will be reduced in this tissue, increasing the risk of infection and disease. Less blood gets to the skin, so that skin will be pale and cool. Lowered blood clotting and less vascular resistance can cause purple and red purpura on the skin and spider veins in the legs. Mucin deposits around nerves can cause carpal tunnel and facial palsy. It's important to understand that adequate thyroid hormone is vital for the health and functioning of our skin and connective tissue; even if you don't have an extreme form of myxedema T3, the active thyroid hormone is essential for all the cells in your body.