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Please note: Ready Health does not engage an immunologist. Our clinicians have helped many patients start to understand their symptoms and reduce their histamine levels to improve the quality of their lives. We are very happy to see patients who think that they may have these conditions, as there seems to be a distinct absence of understanding of the condition currently.

✦ Private MCAS Clinic · UK-wide

Mast Cell Activation Syndrome Consultation

Specialist private assessment and management for MCAS and histamine-driven conditions. Video appointments across the UK, or in-clinic at our Standish, Wigan practice. One flat fee, inclusive of any prescription charges we issue.

30–45 min appointments
Video or in-clinic
CQC-registered clinic

MCAS Consultation

£119
Video or in-clinic · Prescription inclusive
  • Full symptom history & trigger review
  • Tailored medication plan
  • Low-histamine dietary guidance
  • Private prescription issued if appropriate
  • Written follow-up summary
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Regulated by CQC
GMC/NMC/GPhC registered clinicians
No GP referral required
Same-week appointments
Understanding the condition

What is Mast Cell Activation Syndrome?

A chronic, multi-system condition where mast cells — part of your immune system — release mediators inappropriately, producing allergic-type symptoms without a clear cause.

Mast cells are specialist immune cells that store granules of histamine, heparin, tryptase, prostaglandins, leukotrienes and many other chemical mediators. They are designed to release these substances when your body encounters a genuine threat such as a virus, bacterium, or injury.

In Mast Cell Activation Syndrome (MCAS), mast cells become chronically over-reactive and release excessive amounts of these mediators in response to ordinary, harmless stimuli — or sometimes with no identifiable trigger at all. Because mast cells are present throughout the body, symptoms can occur anywhere: skin, gut, lungs, cardiovascular system, nervous system, and beyond.

MCAS frequently overlaps with Histamine Intolerance (HIT), Postural Tachycardia Syndrome (PoTS), Hypermobility Spectrum Disorders / hEDS, Long COVID, ME/CFS, and Fibromyalgia. Around one in five people with histamine intolerance also have MCAS, and will not respond fully to diet and antihistamines alone — they will usually need a mast cell stabilising medication as well.

There is no permanent cure, but with careful assessment, trigger identification, and a tailored medication plan, most patients experience meaningful improvement in symptoms and quality of life. We provide honest, practical guidance rooted in the best available UK clinical evidence — read our in-depth guide in our MCAS blog post for further background.

In-depth reading

Read our detailed explainer: Mast Cell Activation Syndrome — a UK patient guide →

MCAS at a glance

A chronic disorder of inappropriate mast cell mediator release, producing symptoms that fluctuate in severity and frequently cross multiple body systems.

200+
Known mast cell mediators
~20%
Of HIT patients also have MCAS
Multi
Body systems affected
6 mo.
Approx. mast cell turnover
Recognising the signs

Common MCAS symptoms

Because mast cells sit in every tissue of the body, symptoms are diverse, often migratory, and frequently dismissed. Patients typically report episodes that come and go, sometimes daily, sometimes weekly.

Skin

Flushing, hives, itching, dermatographism, angioedema, rashes and unexplained welts.

Cardiovascular

Palpitations, tachycardia, low or labile blood pressure, chest tightness, dizziness, syncope.

Neurological

Brain fog, migraines, headaches, anxiety, insomnia, paraesthesia, cognitive dysfunction.

Gastrointestinal

Abdominal pain, bloating, nausea, reflux, diarrhoea or constipation, food reactions, IBS-like symptoms.

Respiratory

Nasal congestion, sneezing, throat tightness, wheezing, shortness of breath, chronic cough.

Systemic

Profound fatigue, malaise, temperature intolerance, unexplained weight change, chronic inflammation.

Musculoskeletal

Joint pain, muscle aches, bone pain, generalised stiffness, exercise intolerance.

Allergic / Anaphylactoid

Reactions to foods, drugs, insect stings, fragrances or with no identifiable trigger at all.

Identify & eliminate

Common MCAS triggers

Avoiding triggers is the essential first step in MCAS management. During your consultation we help you build a personalised trigger profile across all of these categories.

High-histamine and histamine-liberating foods

A strict low-histamine diet for four weeks is typically recommended to assess benefit. Useful classifications include the SIGHI (Swiss Interest Group Histamine Intolerance) food list — foods graded 2 and 3 should be avoided first, with H1 and L1 foods removed if needed.

  • Fermented foods: aged cheese, sauerkraut, kombucha, soy sauce, vinegar
  • Alcohol (particularly red wine, champagne, beer)
  • Cured and smoked meats, tinned fish, leftovers older than 24 hours
  • Tomatoes, aubergine, spinach, avocado, strawberries, citrus
  • Chocolate, cocoa, caffeine, artificial additives
  • Histamine liberators: shellfish, pineapple, papaya, nuts, wheat

Environmental triggers

  • Temperature extremes — cold, heat, rapid changes
  • UV light and prolonged sun exposure
  • Strong scents, perfumes, cleaning products, smoke
  • Mould, dust, pollen, pet dander
  • Chemical exposures, including pharmaceutical excipients
  • Pressure and friction on the skin (dermatographism)

Medications that can interfere with histamine metabolism

Many prescription drugs inhibit diamine oxidase (DAO) and histamine-N-methyltransferase (HNMT), the enzymes that break histamine down. If you tolerate these without obvious adverse effect, there is usually no need to stop them — but your clinician will review them carefully.

  • NSAIDs including aspirin and ibuprofen
  • Beta-lactam antibiotics (especially amoxicillin) and fluoroquinolones (especially ciprofloxacin)
  • Proton pump inhibitors (especially lansoprazole)
  • Beta blockers, ACE inhibitors, SSRIs and SNRIs
  • Opioids — particularly morphine, codeine, dihydrocodeine, oxycodone and pethidine. Tramadol, fentanyl and buprenorphine have less mast cell effect
  • Those sensitive to aspirin should avoid salicylate-containing products including some toothpastes, cosmetics and food preservatives

Lifestyle & physical triggers

  • Emotional stress, anxiety, and poor sleep
  • Intense or sudden exercise
  • Illness, infection, vaccinations
  • Surgery and general anaesthesia
  • Insect stings and bites
  • Dehydration

Hormonal influences

Oestrogen stimulates mast cells and inhibits DAO — so MCAS and histamine intolerance symptoms are often worse around ovulation and before menstruation, and can change significantly during perimenopause, menopause, pregnancy and with hormone therapy.

  • Perimenstrual flares (days before and during menses)
  • Perimenopausal symptom worsening
  • Oestrogen-containing contraceptives and HRT — careful balancing required
  • Pregnancy can either improve or worsen symptoms dramatically
Evidence-based management

Medication options for MCAS

MCAS management follows a stepwise approach. Your clinician will build a tailored plan, typically starting with H1 and H2 antihistamines and adding mast cell stabilisers or other agents as needed. All prescribing decisions are individualised and reviewed at follow-up.

H1 antihistamines First line

Block histamine H1 receptors and bring clinically significant benefit to most MCAS patients. Frequently required twice daily rather than once.

  • Non-sedating: cetirizine, loratadine, fexofenadine
  • Sedating: diphenhydramine, chlorphenamine
  • Cheap, long-term safe, easy to combine

H2 antihistamines First line

Target gastric and systemic H2 receptors. Usually combined with an H1. Twice-daily dosing is typical in MCAS.

  • Famotidine and nizatidine preferred
  • Cimetidine has many drug interactions
  • Helpful for reflux, GI symptoms, flushing

Mast cell stabilisers Step 2

Prevent mast cell degranulation at the source. Full benefit can take up to 6 months as mast cells turn over.

  • Sodium cromoglicate — oral or inhaled
  • Ketotifen — H1 antagonist + stabiliser (useful with insomnia)
  • Quercetin (OTC) — may be combined with the above

Leukotriene antagonists Step 2

Block leukotriene receptors, another important class of mast cell mediators. Useful where respiratory or inflammatory symptoms dominate.

  • Montelukast — typically once daily
  • Complements H1/H2 blockade
  • Monitored for mood side effects

Supplements & vitamins Adjunct

Several supplements have mast cell stabilising or anti-inflammatory effects and can be useful alongside prescribed medication.

  • High-dose vitamin C — reduces histamine release
  • High-dose vitamin D — immune modulation
  • Quercetin, DAO enzyme supplements

Aspirin & NSAIDs Selective use

Can help some MCAS patients — but may precipitate reactions in a minority. Trial should only ever be under clinical supervision.

  • Low-dose aspirin in selected cases
  • Avoid if aspirin-sensitive
  • Monitor closely for paradoxical reactions

Benzodiazepines Targeted

Have mast cell stabilising effects in addition to their anxiolytic action. Considered carefully where anxiety is a prominent MCAS feature.

  • Lorazepam, clonazepam
  • Short-term or symptom-triggered use
  • Prescribing governance reviewed at each visit

Monoclonal antibodies Specialist

For severe refractory cases. In the UK, omalizumab is only licensed for severe allergic asthma and chronic urticaria and requires specialist referral.

  • Omalizumab — anti-IgE
  • NHS specialist pathway only
  • We can advise on onward referral routes

Brain & ANS retraining Holistic

Neural retraining programmes can significantly reduce symptom burden by calming the autonomic nervous system and dampening threat-response patterns that maintain mast cell activation.

  • Structured nervous-system retraining
  • Pacing, breath-work, vagal tone
  • Complements medication, rarely replaces it

A note on GLP-1 receptor agonists

There is emerging interest in GLP-1 receptor agonists (e.g. semaglutide, tirzepatide) in MCAS, after some patients treated for obesity or type 2 diabetes reported improvement in mast cell symptoms. A 2025 retrospective study by Dr Lawrence Afrin and colleagues reported clinical benefit in 89% of 47 MCAS cases, though most were overweight or obese.

At present there is insufficient evidence to recommend GLP-1 therapy outside its licensed indications of obesity and type 2 diabetes. The appropriate route for patients interested in this approach is enrolment in a clinical trial. We will discuss the evidence honestly during your consultation.

Anaesthesia & surgery in MCAS

If you need surgery, please share your MCAS diagnosis with the anaesthetist. Adrenaline-free local anaesthesia is preferred; H1 antihistamines should typically be doubled for two days before and after surgery; and low-dose naltrexone, if you take it, is usually stopped two days before anaesthesia. We can provide a letter for your surgical team.

What to expect

How your consultation works

A clear, unhurried pathway designed around patients who have often been through years of missed diagnoses.

1

Book online

Choose video or in-clinic (Standish, Wigan). Pay the £119 fee at the time of booking to secure your slot.

2

Pre-consultation

Complete a detailed symptom, trigger and medication questionnaire so your clinician can prepare in advance.

3

Your appointment

A thorough 30–45 minute discussion, examination (if in-clinic), tailored plan and any appropriate private prescription.

4

Follow-up

Written summary of your plan, access to follow-up appointments, and prescription reissue when clinically appropriate.

Transparent pricing

One simple fee

★ Fully inclusive
£119
MCAS Consultation — video or in-clinic

What's included

  • 30–45 minute private consultation with a Ready Health clinician
  • Full history, symptom review and trigger assessment
  • Tailored management and dietary guidance
  • Any private prescription we issue is included in the fee
  • Written follow-up summary
Please note: medication costs are charged separately by the dispensing pharmacy and are not included in the consultation fee. Any tests you may need (e.g. serum tryptase, 24-hour urinary methylhistamine) are quoted separately.
Book your appointment →
Ready to start?

Book your MCAS consultation

Select a time that suits you — video consultations are available UK-wide; in-clinic appointments are held at 22 High Street, Standish, Wigan, WN6 0HL.

Frequently asked questions

MCAS FAQs

MCAS is a clinical diagnosis supported by a pattern of recurrent, multi-system allergic-type symptoms affecting at least two organ systems, objective evidence of mast cell mediator release where possible, and a clear response to mast-cell–targeted treatment. There is no single definitive test. Your clinician will take a detailed history and, where helpful, discuss tests such as serum tryptase or 24-hour urinary histamine metabolites.

The fee covers your full consultation (video or in-clinic), assessment, tailored management plan, and any private prescription we issue at that appointment. Medication costs from the pharmacy and any laboratory tests ordered are charged separately.

Yes. We offer secure video consultations UK-wide. In-clinic appointments take place at 22 High Street, Standish, Wigan, WN6 0HL.

No. You can self-refer by booking directly through the booking tool above. With your permission we will write to your GP after the consultation.

Most patients start with H1 and H2 antihistamines (e.g. cetirizine or fexofenadine plus famotidine or nizatidine), often twice daily. Depending on response, we may add mast cell stabilisers such as sodium cromoglicate or ketotifen, or a leukotriene antagonist such as montelukast. Supplements such as quercetin, high-dose vitamin C and vitamin D are often adjuncts. All prescribing is individualised.

Some patients notice improvement within days of starting H1/H2 antihistamines and trigger avoidance. Mast cell stabilisers can take up to six months for full effect, as mast cells turn over slowly. MCAS management is usually a stepwise process with regular review.

No. Ready Health does not engage an immunologist. Our experienced GMC-registered clinicians have helped many patients begin to understand their symptoms and reduce their histamine levels to improve their quality of life. We welcome patients who suspect they may have MCAS, given the widespread lack of understanding of the condition.

Yes. These conditions commonly overlap with MCAS. We take the overlap seriously and will address it as part of your care plan.

Yes. Follow-up consultations can be booked through the same system. Prescription reissue appointments are shorter and lower cost where clinically appropriate.

Private clinics do not provide emergency care. If you are having a severe allergic or anaphylactic reaction, call 999 or go to your nearest A&E immediately. Carry any prescribed adrenaline auto-injectors at all times.

Start understanding your symptoms today

Book a private MCAS consultation with Ready Health — £119, video or in-clinic, prescription inclusive.

Book Now →