Hypothyroidism (an underactive thyroid) may cause increased bruising.
Hypothyroidism develops when the thyroid gland can’t release enough thyroid hormone when needed.
While increased bruising isn’t one of the symptoms commonly associated with hypothyroidism, it might happen if hypothyroidism affects the mechanisms that keep blood from leaking out of a blood vessel.
A bruise or contusion occurs when small blood vessels known as capillaries leak blood in response to an injury. The blood pools under the skin, causing a bruise.
If you’re experiencing increased bruising, it’s best to talk with a doctor to determine the possible cause.
Hypothyroidism can make bruising more likely by:
- making it take longer for blood to clot (by reducing blood clotting factors, which are proteins in the blood that cause it to clot)
- weakening capillaries and making them more likely to leak blood
In addition to increased bruising, weakened capillaries and reduced blood clotting factors can also cause:
- bleeding, such as nosebleeds, happening more often and taking longer to stop
- bleeding gums when brushing or flossing teeth
- heavy menstrual bleeding
It’s best to talk with a doctor if you’re experiencing unexplained bruising or bleeding. They can run tests to determine the cause and recommend a treatment plan.
Various health conditions can cause increased bruising and bleeding, including:
- certain medications, such as blood thinners or aspirin
- supplements with blood-thinning effects, such as aloe, ginger, ginkgo, garlic, green tea, grapefruit, ginseng, and oregano
- a low platelet count (thrombocytopenia)
- nutrient deficiencies
- blood clotting disorders, such as Von Willebrand disease or hemophilia
- Ehlers-Danlos syndrome
- Cushing syndrome
- kidney or liver disease