Mast Cell Activation Syndrome (MCAS)
When Your Body Overreacts to Everyday Triggers
Mast Cell Activation Syndrome (MCAS) is a chronic condition where the body’s mast cells – responsible for allergic and inflammatory responses – become overactive and release chemicals inappropriately. This overreaction can affect multiple systems in the body and lead to a wide range of unpredictable, often distressing symptoms.
People with MCAS may experience rashes, itching, flushing, headaches, digestive problems, brain fog, fatigue, shortness of breath, and even anaphylaxis – like reactions – often without a known allergy or clear trigger. What makes MCAS so difficult to identify is that symptoms can come and go, vary in intensity, and look different from person to person.
Symptoms of Mast Cell Activation Syndrome (MCAS)
Skin & Allergic-Type
- Itching
- Hives or Rashes
- Swelling (Face, Lips, or Tongue)
- Flusing (Sudden Facial Redness)
Systemic & Digestive
- Nausea or Vomiting
- Diarrhoea or Constipation
- Abdominal Cramping or Bloating
- Dizziness or Fainting
- Fatigue
- Brain Fog
- Shortness of Breath
- Palpitations
A Condition That’s Easy to Miss - But Hard to Live With
MCAS is frequently underdiagnosed or misdiagnosed. Symptoms are often mistaken for anxiety, stress, or unrelated issues. Many individuals spend years seeking answers, unsure why their body seems to “overreact” to food, environmental factors, medications, or even heat and exercise.
MCAS often overlaps with other complex conditions like Hypermobile Ehlers-Danlos Syndrome (hEDS) and Postural Orthostatic Tachycardia Syndrome (POTS), which adds to the diagnostic challenge. The frustration of being dismissed or misunderstood takes a toll—not only on physical health but also on mental and emotional wellbeing.
How ConnectED Helps Bring Clarity
ConnectED was built with people like you in mind. Our app allows you to track your symptoms comprehensively and generate a personalised report that highlights potential patterns and links to conditions such as MCAS. While ConnectED is not a diagnostic tool, it supports better conversations with your healthcare provider by giving them structured, evidence-based insights into your experience.
In doing so, it bridges the gap between what you’re feeling and what your doctor sees—empowering you to move forward with greater confidence and clarity.