Mastocytosis: before, during and after diagnosis
SPONSORED CONTENT
Living with mastocytosis means navigating unpredictable, sometimes life‑threatening reactions alongside chronic pain, fatigue and fear. In April 2026, RARE Revolution hosted our 25th RARE Rev-inar. Sponsored by Blueprint Medicines, a Sanofi company, this discussion sees patient advocate Shawna Hull share her own personal journey with mastocystosis, and physician-scientist Dr Polina Pyatilova discuss the complexities of the disease and how a strong patient-doctor relationship allows for optimal care
Written by Emma Bishop, RARE Revolution
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Dr Polina Pyatilova, a dermatologist and physician–scientist working in Berlin, sets the scene, explaining that mastocytosis is a disease characterised by an excess amount of mast cells in the body, due to a genetic variation, often in the KIT gene. The variation means mast cells keep growing and stay constantly active without trigger. There are two main types of mastocytosis; cutaneous, where mast cells are limited to the skin, and systemic, where mast cells are in the bone marrow and throughout the body, meaning multiple organs, such as the skin, gut and bones can be affected.
Systemic mastocystosis can be further categorised as non-advanced disease (or indolent), which is most frequent in adults and is characterised by slower disease progression, and advanced disease, a more aggressive form which typically involves organ damage. In some cases, both can occur together.
Shawna Hull is a patient advocate from Georgia, US, who lives with both cutaneous and systemic mastocytosis. She was diagnosed following a 12-year diagnostic odyssey and explains how early symptoms were dismissed. “When I was younger, I always had issues with the heat and the sun causing rashes, but somebody would always find an excuse to dismiss these things.” Multiple trips to the emergency room (ER) were attributed to food poisoning, which Shawna now knows were anaphylactic reactions. She also began experiencing reactions to food and smells but no one ever “put the puzzle pieces together.” Speaking of her long search for answers, Shawna reflects, “You trust that the doctors know more than we know, so you just roll with it.”
The variability of mastocytosis means it is often described as a spectrum condition, which Shawna expands upon. “The spectrum describes the unpredictability and intense symptoms that are triggered by heat, smells and certain foods. We’re affected in many ways from the physical, the neurological and the psychological.” The physical symptoms can include flushing, hives, chronic bone pain, diarrhoea and reoccurring anaphylaxis. Neurological issues can involve brain fog, irritability and memory issues. For Shawna, the psychological effects of living with mastocytosis cause the greatest burden.
“The biggest thing is the fear of the unpredictability. You don’t know what’s going to trigger you so you can experience PTSD (post-traumatic stress disorder) like symptoms when thinking about doing anything.”
With many HCPs unaware, Polina outlines some of the early clinical clues that multiple specialties should be on the look out for. Recurrent or severe anaphylaxis, especially from insect stings or unclear triggers is a major red flag, and Polina advises that each patient experiencing anaphylaxis should have serum tryptase checked to aid early diagnosis. Skin lesions are often found when a patient is examined by a dermatologist but can be missed by other specialties. Unusual and severe osteoporosis or fractures especially in young people can be a further red flag.
Persistent gastrointestinal (GI) symptoms without a clear explanation should also prompt further investigation, with mastocytosis considered. Polina explains that lastly, neurological symptoms, such as brain fog and cognitive issues, are rarely in isolation and usually occur with other symptoms of mastocytosis.
She urges clinicians to connect the dots when these multiple symptoms appear, to reveal the “big picture” that may point to mastocytosis.
As is commonplace in the rare disease community, Shawna’s journey to diagnosis took over a decade. Initially diagnosed with cutaneous mastocystosis in 2012, Shawna was told it was unlikely to become systemic and to have her tryptase levels checked annually. In 2018 a fall resulted in her breaking her hip and femur resulting in emergency surgery. Doctors concluded she had osteoporosis. She recalls her surprise as this diagnosis: “I thought, I’m 49, how can I have osteoporosis?”
After the surgery, Shawna experienced severe, chronic bone pain, so excruciating it was hard for her to function. At the time, she was also seeing a doctor for irritable bowel symptoms and a cardiologist for heart palpitations.
“But still nobody put the pieces of the puzzle together. If they had, they would have realised this is systemic mastocytosis.”
It was during an annual check-up that Shawna’s elevated tryptase levels caused concern. Within a month she had a bone marrow biopsy and was diagnosed with systemic mastocytosis.
Polina explains that the core diagnostic tool kit is a thorough clinical assessment, considering a full symptom history, looking at skin involvements, GI issues, neurological symptoms and bone pain and fractures. This then determines the next steps taken towards testing and treatment. For Polina, the KIT mutation test is her “dream test”. She expands:
“This genetic analysis [KIT mutation test] is the most important. It not only can lead to a diagnosis, but it can tell us how many cells are mutated and how high the burden of mutation is.” Even before a bone marrow biopsy, it can give a strong indication of mastocytosis and disease burden.
The second test is checking serum tryptase levels—mast cells contain tryptase and so blood tryptase correlates with total mast cell load in the body. It supports diagnosis and gives an indication of how many mast cells are present. However, symptom severity does not always correlate with tryptase levels or mast cell numbers, notes Polina. Beyond mast cell specific tests, full blood counts and bone marrow biopsies are also carried out.
For Shawna finally receiving a diagnosis and being heard was a pivotal moment in her life:
“You’re so relieved because somebody finally has heard you, they put the pieces together and it explains everything. We have a unique kind of exhaustion that comes from managing our symptoms and fighting for people to recognise, to hear us and believe us. You often feel like you’re being dismissed and you start doubting your own experiences. It was such a huge, emotional win to know that somebody believes me.”
For a complex condition with such variability Polina advocates for clinicians taking their time to explain mastocytosis to newly diagnosed patients with measured and empathetic communication. Providing them with clear explanations, trusted information and resources, structured tools, such as questionnaires and dairies, and with planned follow up appointments can help empower patients at the start of their medical journey and reduce the overwhelm.
To accept her diagnosis Shawna says she had to, “succumb to the new normal and grieve the old life before diagnosis.” She shares how upon receiving a diagnosis the fear hits, and it can be hard to convey this to other people.
“People don’t understand the life that you live in fear that something can make you anaphylactic. You try to hide it but it’s always there in the back of our minds.”
Constant planning and preparation are essential for such an unpredictable condition. Shawna always carries epinephrine and has an emergency binder full of pertinent information detailing her diagnosis and safe and unsafe treatment options. Such is the importance of communicating her needs to others, urgently, Shawna keeps copies in her car, at home and has a letter on her back door in case someone finds her in an emergency.
Shawna explains how her condition has meant readjusting her expectations of what she can achieve. “You can still do the things you want to do, but you’re not going to be able to do it all on the same day. I’ll have a list of 10 things, and I’ll get maybe two done but I feel like it’s better than nothing.”
Self-advocacy is extremely important, especially when conveying rare and often misunderstood conditions. “You have to advocate for yourself,” advises Shawna. “I will always introduce myself to every new doctor as ‘I’m the first systemic mastocytosis patient you’re ever going to meet’, explain my diagnosis and tell them how to treat me. It’s just part of who we are now.”
Shawna also speaks of the importance of community and the value in sharing lived experience. Soon after her diagnosis she reached out to, and joined support groups.
“It’s such a relief to have a place where you can have an open dialog and get help from others who’ve been through it longer.”
Polina also believes in the coming together of people. believing that optimal care for those with mastocytosis comes from a strong partnership between patients and their physicians, with clear and open communication. Learning and identifying triggers and building safety through education and planning, and not just avoidance, helps patients take back some control and improves their quality of life.
“You cannot exclude all triggers from your life, so we focus on having a normal life, and we build safety with a mastocytosis passport, clear steps on what to do and regular training in how to use adrenaline. Families also needs to know what to do. With good communication with the physician, patients can feel that they can be safe.”
For Polina, psychological support for people with mastocytosis should be part of routine care, and that clinicians should actively look for signs of psychological impact and burden.
“From our perspective, as physicians, we need to try to identify and understand how severe the patient is impacted.”
She acknowledges that not everyone feels comfortable talking about their mental health and may feel some stigma around it. Pre-appointment questionnaires can be effective tools to enable individuals to think more about how their condition affects their day-to-day life and convey it in ways they may not feel able to directly communicate to their clinician.
Horizon scanning the future of mastocytosis care, Polina believes the outlook can be bright. Improved diagnostic tools, especially KIT mutation kits, will help identify more patients earlier and more accurately. Targeted therapies are also changing the way patients are treated, moving away from purely symptom management, and she anticipates a future shift from trigger-avoidance toward treating the underlying disease more effectively.
For Shawna, learning how to manage her condition, and understand her triggers is a lifetime role. Yet despite the change to her lifestyle and the persistent state of vigilance, she is determined not to live in constant fear.
“I’m still learning, it’s changing every day. I could eat something today that I’ve eaten all my life and be anaphylactic. That’s where you get the trauma because you don’t know what’s going to trigger you. But I’m not going to live my life where I’m scared of everything. I’m going to keep on fighting.”
To watch the full interview please visit: https://www.youtube.com/playlist?list=PL08zb_pnbXSth5oGJd_wHyLe_pt1FjiOk
This article was created from insights from our 25th RARE Rev-inar, Mastocytosis: before, during and after diagnosis, which was supported by Blueprint Medicines.
Blueprint Medicines have had no editorial control or influence over this copy (other than for compliance review and to check factual accuracy) and opinions are those of the contributor alone.
