Mast Cell Activation
Syndrome

MCAS Symptoms

• Sneezing or runny nose

• Watery eyes

• Itching (pruritus)

• Hives (urticaria)

• Swelling

• Abdominal pain or nausea

• Diarrhea

• Heartburn or GERD

• Fast heart beat (tachycardia)

• Trouble breathing or wheezing

• Migraines

• Anxiety or panic attacks

• Fibromyalgia or chronic pain 

What is Mast Cell Activation Syndrome?

Mast Cells are a part of our immune defense system. When we encounter a foreign substance or irritant, the immune system wants to get rid of it quickly by washing it away or removing it from the body.

Sneezing, runny nose and watery eyes are some ways the immune system removes these substances quickly. These immediate responses are a result of activation of Mast Cells by triggers such as allergens, foods, toxins, injury or infections.

Mast Cells release chemicals such as histamines that set off reactions throughout the body to remove a foreign, irritating substance. Once the substance is removed, Mast Cells should return to an inactive state and histamine and other inflammatory chemicals cleared from the body. When Mast Cells continue to be active or histamines are not cleared, Mast Cell Activation Syndrome (MCAS) results.

This is different from Mastocytosis which is an accumulation of too many Mast Cells in one area of the body. If Mast Cells accumulate in the skin, Mastocytosis rash results.