Could my symptoms fit MCAS?

MCAS can cause a wide range of symptoms because mast cells are found throughout the body. Symptoms affect several body systems, can come and go, and may change over time.

People may experience symptoms such as flushing, itching or hives, digestive problems, headaches, brain fog, fatigue, palpitations, breathing difficulties or allergy-type reactions. However, these symptoms can have many different causes and experiencing them does not necessarily mean you have MCAS.

You can find out more about symptoms here.

When and how to seek medical advice

If you have persistent, recurring or unexplained symptoms that are affecting your health or daily life, speak to your GP. They can consider your symptoms as a whole, investigate other possible causes and decide whether further tests or referral are appropriate.

Your GP may find it helpful to receive a copy of our primary care guide and they are welcome to get in touch for more support from our clinical advisors.

Some symptoms require urgent medical attention. Severe breathing difficulty, collapse or a serious allergic reaction should be treated as a medical emergency.

What information to record

MCAS symptoms can fluctuate, so having a clear record can help your healthcare professional understand what is happening over time.

You may find it helpful to keep a simple record of your symptoms, when they occur, how long they last, possible triggers, medicines or treatments taken and whether these helped. Photographs can also be useful for visible symptoms such as flushing, swelling or rashes.

You don't need to record everything perfectly - focus on information that helps show patterns. You may wish to use our symptom log as a record.

Preparing for a GP appointment

A little preparation can make it easier to explain a complicated symptom history in a short appointment. Many people find it helpful to take a brief summary of your main symptoms, when they began, which body systems are affected and how they impact your daily life. You could include relevant diagnoses, medications, previous investigations and any patterns you have noticed.

Rather than trying to prove that you have MCAS, it is often helpful to focus on explaining what is happening and asking your GP to help investigate the possible causes. You can read more about preparing for your appointment and working with your GP here.