Author response

In their letter, the British Society for Allergy and Clinical Immunology (BSACI) criticise our suggestions on the role of mast cells in managing long COVID based on lack of evidence, and the risk of triggering unnecessary referrals to immunology and allergy clinics.

Our paper was written over a year ago, before long COVID clinics and in the face of an urgent need to bridge the gap between evidence-based practice and clinical experience in the face of a widening health emergency. Given the slow pace of research, we are no further on in ‘NICE-standard’ evidence, yet we now have 1.7 million people with long COVID, half of whom with symptoms for over a year and over a million with their working lives significantly impacted.¹ For GPs to sit back and take the stance of the BSACI would be a gross failure to meet the needs of our patients. Our recommendations on treating urticaria do not step beyond the Scottish Intercollegiate Guidelines Network guidance cited, except in considering it reasonable to extend the symptomatic scope of treatment. Referral in severe cases of angioedema or anaphylaxis is within current guidance.

Ongoing research in long COVID suggests a complex set of immunological,^2,3 platelet, and endothelial abnormalities,⁴ possibly linked to viral persistence.⁵ Testing antihistamine response and being aware of potential dietary triggers are simple, low-risk interventions that have support from clinicians treating patients with long COVID. A clinical trial of antihistamines, led by University College London Hospitals, is about to start (STIMULATE-ICP), but will be over a year in reporting. We do not consider that mast cell disorder is the cause of long COVID, but a potential symptom target, alongside postural orthostatic tachycardia syndrome, and treating either or both if present is something that GPs can offer now to help many patients with long COVID.

• © British Journal of General Practice 2022