Why Do My Muscles Itch?

Itchy muscles are common, particularly during physical activity. This sensation—also called "pruritus"—is often felt under the skin and isn't always relieved by scratching. In some cases, itchy muscles can also be a symptom of an underlying medical condition.

This article discusses various causes of itchy muscles and how to treat this symptom.

What Causes Itchy Muscles?

Itchy muscles can occur with exercise, as a symptom of a medical condition, or from other causes, such as side effects of medication.

Exercise

Itchy muscles are a common side effect of exercise. This sensation typically affects the muscles being used during the activity. For example, "runner's itch" is a term that describes the itchy sensation in the legs that often occurs after running.

During exercise, the body releases a chemical called histamine. This neurotransmitter causes your blood vessels to dilate (get wider), which helps deliver oxygen to your muscles. As the vessels dilate, nearby nerves are stimulated, causing an itching sensation.

However, histamine also initiates the allergic reaction that occurs when you encounter an allergen—anything your body identifies as "foreign"—even if it is harmless. For some people, exercise can cause an allergic reaction.

Exercise-induced urticaria is a condition that occurs when exercise triggers an allergic response. In addition to an itching sensation, other symptoms can include:

• Hives
• Stomach pain
• Headache
• Difficulty breathing
• A choking sensation
• Red skin
• A swollen face or tongue
• Swollen hands

Itchy muscles from exercise might not need treatment. In most cases, the uncomfortable sensation subsides as you recover from activity.

Exercise-induced urticaria can sometimes be managed by avoiding high-intensity exercise, staying cool during activity, and wearing loose-fitting clothing. Antihistamine medications are also used to help prevent or treat symptoms that occur with this condition.

Your healthcare provider might also prescribe an injectable medication called epinephrine to be used during a serious allergic reaction.

Neuropathic Itch

Muscle itching can be caused by miscommunication between the brain and nerves throughout the body. This condition is called neuropathic itch.

Neuropathic itch can occur with conditions such as:

• Fibromyalgia
• Multiple sclerosis
• Chronic fatigue syndrome
• Shingles
• Stroke
• Radiculopathy
• Nerve damage

Neuropathic itch is difficult to treat, and there are no research-backed effective treatments. Some people report improvement with use of over-the-counter capsaicin patches or Gralise (gabapentin).

Compounds called cannabinoids—produced from the cannabis plant—might also be beneficial in treating neuropathic itch, but more research is needed in this area.

In many cases, neuropathic itch leads to scratching, but unfortunately, this does not relieve the itch. Instead, repeated scratching can cause damage to the skin, leading to wounds and infection.

Other Causes of Muscle Itch

Muscle itching can be a side effect of medications. Examples include aspirin, blood pressure medication, and opioids. If symptoms are severe, medications might need to be replaced.

Internal itching sensations can also occur during pregnancy. A condition called intrahepatic cholestasis of pregnancy (ICP) can develop when bile builds up in the liver. In addition to itching, this condition can cause digestive issues and difficulty sleeping. ICP resolves on its own after childbirth.

Managing the Itch

Home remedies can help decrease the sensation of itchy muscles—especially if the underlying cause can't be effectively treated.

• Cool it down: After exercise, take a cool shower or apply a cold pack for 10 minutes to reduce blood flow to your muscles. Ice can also help temporarily distract your brain from the itchy feeling.
• Calm your mind: Itching can be very frustrating. Stress management techniques such as meditation and progressive muscle relaxation can help calm your mind.
• Rub gently: Lightly massaging your itchy muscles can help decrease uncomfortable sensations.

Summary

Itchy muscles are a common symptom. Itchiness can occur during or after exercise, due to increased blood flow to working muscles.

This symptom can also be a sign of underlying medical conditions that affect the nervous system, such as multiple sclerosis or shingles. In some cases, itchy muscles occur with pregnancy or as a side effect of medication.

Treatment for internal itching sensations depends on the specific cause. In some cases, there is no treatment, but distraction techniques can help.

A Word From Verywell

Itchy muscles are common and usually not a cause for worry. However, if you notice that you're experiencing this symptom frequently—particularly if it isn't during or after exercise—talk to your healthcare provider.