I Think My Child Has MCAS: What Do I Do Now? – A Step By Step Guide.

Written by student dietitian Sam Coates, checked by registered dietitian Nishti

It started with something small. Perhaps your child came home from a birthday party with flushed cheeks and an upset stomach. Then there was the rash after playing outside on a warm day, the dizziness the teacher mentioned during a PE class or the mood swings after dinner. These incidents seemed random and unrelated at first, but now you’re starting to wonder whether there is a link - could it be Mast Cell Activation Syndrome (MCAS)?

What are Mast Cells?

Mast cells are an essential part of our immune system and are integral to our bodies ability to respond to allergens, infections and injuries that may cause us harm. These specialised cells are found all over the body but are especially concentrated at points where the body meets the outside world directly, such as our skin, or where organs come into contact with items that originated outside the body, such as the lungs which comes into airborne particles when we breathe, or our digestive tract which comes into contact with food we have consumed. Mast cells are our bodies first line of defence, releasing chemicals like histamine, tryptase, and prostaglandins in response to perceived potential threats. In a healthy system, this response is tightly regulated.

However, in MCAS, Mast cells become overactive and release these chemicals inappropriately. This dysregulation can cause a variety of symptoms across several body systems, including, but not limited to:

• Skin: flushing, rashes, hives, or itching.
• Digestive System: abdominal pain, diarrhoea, nausea, or vomiting.
• Cardiovascular System: rapid heartbeat, low blood pressure, or fainting.
• Respiratory System: nasal congestion, wheezing, or difficulty breathing.
• Nervous System: brain fog, dizziness, headaches, or anxiety.
• Behavioural Changes: irritability, fatigue, or mood swings.
• Joint Issues: pain or swelling in joints, which may be intermittent or persistent.
• Cardiac Symptoms: Palpitations, chest pain, or feeling faint.

MCAS symptoms can feel unpredictable, are wide-ranging and often vary from person to person, making MCAS particularly challenging to identify and diagnose.

Nevertheless, understanding MCAS, its symptoms and causes will help you articulate your concerns clearly to healthcare professionals. We hope this Step-by-Step guide will provide a guiding hand on navigate your journey of re-discovering your child’s health.

Step 1: Learn About MCAS

Before speaking to a healthcare provider, familiarise yourself with what MCAS is, what symptoms are associated with it, and consider how it presents within your child and therefore, why you believe MCAS could be the cause of your child’s ill health.

Mast cells play a key role in the immune system, releasing chemicals like histamine in response to perceived threats. In MCAS, these cells become overly reactive, releasing too many inflammatory chemicals without an appropriate trigger.

In the UK, MCAS awareness is gradually increasing, but it is still relatively unknown among many healthcare providers. This can make accessing appropriate care challenging. Educating yourself with reputable sources such as the NHS website, Allergy UK, Mast Cell Action or patient support groups can help you feel prepared when discussing your concerns with medical professionals.

Useful Resources

• The Mast Cell Action UK: https://www.mastcellaction.org
• NHS Resources on Allergies: https://www.nhs.uk
• British Medical Journal: https://bestpractice.bmj.com/topics/en-gb/3000310
• MCAS Support Groups: Mast Cell Action facilitate support groups online and there are several forums and online communities on social media.

Step 2: Keep a Symptom Diary

Since MCAS symptoms are diverse and can mimic other conditions, keeping a detailed record of your child’s symptoms is invaluable when trying to identify patterns or triggers.

Be sure to include:

• The type of symptoms (e.g. rashes, stomach pain or dizziness). Taking pictures / video’s can also be really helpful when trying to describe the type and severity of symptoms to others.
• The timing of symptoms (e.g. immediately after eating, during a stressful event, after a bath or shower).
• Any potential triggers (e.g. specific foods, environmental changes or physical exertion).
• The duration and severity of each episode.
• Any patterns you notice (e.g. worse symptoms in certain seasons or at particular times of day).

Having this information organised and ready can help healthcare providers identify potential triggers, narrow down possibilities and identify appropriate referrals or tests required.

Step 3: Consult Your GP

Start with your GP. Bring your symptom diary and be prepared to explain why you suspect MCAS. While many general practitioners in the UK may not be familiar with MCAS, they can rule out more common conditions with similar symptoms, such as allergies, gastrointestinal disorders, or autoimmune diseases.

Top Tip: consider bringing printed information or links to reliable resources about MCAS when meeting your GP.

Following these initial investigations, if your child’s symptoms remain unexplained ask for a referral to a specialist.

Specialists who may be able to help include:

• Allergists/Immunologists: These specialists are familiar with histamine-related conditions and can assess for mast cell involvement.
• Gastroenterologists: If your child’s symptoms are primarily digestive, this type of specialist may help.
• Rheumatologists: If joint pain, fatigue or systemic inflammation are prominent, a rheumatologist’s insight may be valuable.

Note: Under the NHS system, referrals may take time, so it’s important to be persistent and follow up if needed.

You can also explore private healthcare options if you are able. Many private clinics in the UK offer faster access to consultations for complex and rarer conditions.

Step 4: How Can My Doctor Diagnose MCAS?

There is no single test to diagnose MCAS, but a combination of blood tests, lab results, documented symptoms and response to treatments, can lead to a diagnosis.

Tests may include:

• Blood Tests:To measure markers like tryptase, histamine, or prostaglandins.

• Urine Tests: To check for elevated levels of mast cell mediators, such as methylhistamine or prostaglandin D2.
• Skin or Bone Marrow Biopsies: In rare cases, these may be needed to assess mast cell activity.

In the UK, some of these tests may only be available through specialist clinics or private healthcare providers.

Step 5: If My Child Has MCAS, What Can Doctors Do to Help?

Doctors can play a crucial role in managing MCAS by tailoring medications based on your child’s symptoms and triggers. Common interventions include:

• H1 and H2 Antihistamines:  Medications such as Loratadine, Famotidine and Cetirizine block either H1 or H2 histamine receptors and therefore can help to reduce symptoms like itching, flushing, and stomach pain.
• Mast Cell Stabilizers: Medications like Sodium Cromoglycate or Ketotifen can help prevent mast cells from releasing inflammatory chemicals.
• Leukotriene Inhibitors: Drugs like Montelukast may help with respiratory or systemic symptoms.
• Individual Symptom Management: Doctors may also be help with addressing specific issues, such as prescribing anti-nausea medication, laxatives and pain relief.

Working closely with your child’s GP or specialist to ensure all treatments are safe, appropriate and effective is essential.

What Can a Dietitian Do to Help?

A registered dietitian can be invaluable when navigating the dietary challenges of MCAS. Many parents’ resort to restrictive diets to try and manage symptoms, eliminating high-histamine foods or other potential triggers. While this can provide temporary relief, overly restrictive diets carry risks, including nutrient deficiencies, poor growth and development and result in long term negative impacts on your child’s overall health.

A dietitian can:

• Identify Triggers: Help determine which foods may be triggering your child’s symptoms.
• Create a Balanced Plan: Design a diet that minimises triggers while ensuring your child gets the nutrients they need for healthy growth and development.
• Monitor Nutritional Status: Regularly assess for signs of deficiencies and recommend supplements if necessary.
• Educate and Support: Provide guidance on food preparation, label reading, and managing symptoms without unnecessary restrictions.
• Reintroduce Foods: Help you to navigate the reintroduction process in a planned and graded approach to minimise the risk of flaring symptoms, whilst helping your child regain diversity and enjoyment within their diet.

Seeking support from a dietitian ensures that your child’s diet remains safe, balanced and sustainable, while addressing MCAS-related symptoms.

Step 6: Advocate for Your Child

Getting a diagnosis for MCAS can be a lengthy process. Misdiagnoses are common, and many parents encounter scepticism along the way. However, you know your child best. If you feel their symptoms are being dismissed, or a diagnosis doesn’t accurately represent what is happening for them, don’t hesitate to seek second opinions or explore alternative specialists.

Joining UK-based support groups or forums for parents of children with MCAS can provide valuable advice, suggest specialists, and offer emotional support. Additionally, they can provide you with a community of individuals who are also trying to navigate this tricky road.

Final Thoughts

Pursuing a diagnosis for MCAS can be daunting, but with persistence and the right support, you can find answers. By educating yourself, keeping detailed records, and seeking out knowledgeable professionals, you’re taking essential steps to help your child feel better.

Remember, you’re not alone in this journey. There is a growing community of parents, patients, and healthcare professionals who understand the challenges of MCAS and are here to support you.

Need help? Book a free inquiry call with Nishti here.