At 15, Emma Widmar was a healthy athlete in Wisconsin before her body began to unravel.
She developed facial swelling, unexplained prolonged menstrual bleeding, fainting spells and food reactions so extreme that she required a feeding tube. She lost 60 pounds.
Over a decade, she saw more than 50 specialists, each treating a symptom, but none identifying the cause. Some blamed allergies; others accused her parents of Münchausen by proxy. Her family maxed out credit cards and drained their savings, driving across state lines for appointments.
Only after years of uncertainty was she told she has a condition that remains controversial in parts of the mainstream medical community — and is notoriously difficult to diagnose.
The disorder? Mast cell activation syndrome (MCAS), which occurs when mast cells — immune cells responsible for allergic response — overstimulate and misfire, releasing inflammatory chemicals like histamine throughout the body.
The condition is elusive and shifts without warning. Patients eat normally one day, then go into anaphylaxis the next. Reactions can be triggered by stress, environment or even sunlight.
Because symptoms are unpredictable and aren’t confined to a single organ system, patients bounce from specialist to specialist in search of answers.
That was true for Lena Dunham, who recounted her experience with MAS in her recent memoir, “Famesick.” The singer Halsey has also shared her diagnosis, as have Kate Beckinsale, Bethenny Frankel, Solange Knowles, Billie Eilish, Jameela Jamil and Olympic gymnast McKayla Maroney.
Doctors receive only “one minute” of mast cell education in medical school, says Dr. Lawrence Afrin, a hematologist and leading MCAS researcher. That education is limited to a rare mast-cell cancer — not the greater disorder.
Formally classified in 2016, MCAS remains poorly understood and unrecognized, even as diagnoses rise post-COVID, amid chronic stress and environmental exposures.
Studies show women are diagnosed 4-5 times more often than men, likely due to hormonal fluctuations. Experts say their symptoms are often dismissed. Patients report being told their condition is anxiety — while their bodies worsen.
A “nightmare” of dismissals
Jenna Lee Jane can pinpoint the moment her body was never the same.
After a sinus surgery went awry when she was a teen, she developed hives, swelling and “crazy rashes” that spiraled into gastrointestinal complications. She documented her symptoms religiously in a journal while visiting a revolving door of doctors.
“I had seen allergies, rheumatologists, new primary care doctors, neuro, cardio, electrophysiology — everything,” she said.
As she deteriorated, she abandoned plans for college in New York. At her lowest, she spent a year mostly bedbound under constant care and lost over 20 pounds.
“I felt completely out of control of my body and mind,” she said. “Just feeling like I’m constantly on the brink… Am I losing it?” she said, adding she suffered bouts of psychosis and hallucinations.
Instead of answers, she was met with suspicion. One doctor accused her of fabricating symptoms or having an eating disorder — a theme that shaped her experience for years.
“He gaslit me for five years. It was a nightmare,” she said, adding that fear became constant in her life.
With no diagnosis, she searched for answers outside medicine. Online forums and support groups echoed her symptoms, but it was a chance encounter with Emma Widmar that pointed her to MCAS.
Today, she survives on a handful of “safe” foods and hypoallergenic formula. She has gone nearly seven years without eating fruit or vegetables.
Kiss of anaphylaxis
For Caroline Cray, symptoms began during an emotionally abusive relationship in college. Although she had a history of allergies, foods she had eaten her entire life began triggering severe reactions, causing near-daily anaphylaxis and repeated hospital visits.
“It felt like someone was grabbing my throat and squeezing it,” she said of her symptoms.
Reactions became impossible to predict. Even safe moments carried risk — a kiss from her boyfriend after eating triggered another episode. She lost 30 pounds managing symptoms and emergencies, shifting from athlete to patient.
“I felt like a ghost,” she said, recalling panic-filled nights and feeling completely unsafe in her body.
Though she received an MCAS diagnosis rather quickly relative to others, managing it remains a challenge. She juggles cocktails of antihistamines, Xolair injections, and a strict diet of oats and baby formula. Her creative recipes using these two ingredients have gained her an online following.
Looking back, she believes the relationship played a significant role in her illness.
“I don’t think I would have gotten sick if he weren’t a factor,” Cray said. She now jokes that she is “allergic” to stress and lack of sleep, highlighting a link between her nervous system and MCAS that doctors are only starting to understand.
Medical blind spot
MCAS exposes a critical gap in modern medicine. Diagnosis relies on pattern recognition, but MCAS defies such patterns, making the condition tough to classify.
“It’s not easy to learn it when you haven’t even been taught that such a disease exists,” said Afrin. “The truth of the matter is, every doctor has been seeing this left and right all day long; they just didn’t recognize it.”
Early research suggests that 20% of the population could have some sort of mast cell disorder, making it as common as diabetes.
But managing MCAS presents its own challenges because there are thousands of diagnostic markers, many of which are difficult to measure or degrade quickly, says Afrin. A 2025 study found that limited physician knowledge and experience, along with complex diagnostic criteria, affect patients’ quality of care.
Afrin says patients must track their symptoms, commit to long specialized appointments, and undergo a gradual elimination of potential triggers. This is hard in insurance-based systems, so many turn to private specialists, where costs can quickly mount.
“There’s no shortcut to trial and error here,” Afrin said, explaining that treatments must be introduced one at a time to determine what works.
Clinicians also say treatment cannot rely on medication alone. Dr. Stephanie Peacock, a functional doctor who treats MCAS, notes that many patients arrive after years of dismissal with bodies locked in chronic stress.
“Nervous system regulation is half the battle,” Peacock said, explaining that mast cells can directly influence the body’s stress response and create a feedback loop when activated.
The toll
The cost is not just medical but also psychological, financial and, for many, all-consuming.
Studies show MCAS patients have higher anxiety and depression rates, often improving once diagnosed. Many say the emotional toll is worsened by years of dismissal, but the financial impact can be just as extreme.
Alexa Greenfield spent years searching for answers to her debilitating symptoms that followed multiple bouts of Covid. At her worst, she said she was “allergic to the sun,” suffered brain fog and fatigue so severe she relied on Adderall just for basic functions, leaving her bedridden and depressed.
Repeated failed interventions and failed treatments inspired her to research her symptoms, where she finally learned about MCAS. She estimates spending $150,000 out of pocket over five years.
For many patients, those costs are unavoidable. Because MCAS is poorly understood and inconsistently recognized, much of the testing and treatment falls outside standard insurance coverage.
For Tammy Nearon, this meant changing daily life to keep her daughter alive.
“At one point, all she could eat was meat from Australia,” she said. “Was I late on bills? Absolutely.”
After her daughter passed from MCAS complications, Nearon is still rebuilding financially.
“Credit cards maxed out — it doesn’t just disappear,” she said.
For some, the illness becomes disabling, forcing them out of work and into long periods of isolation.
Finding a network
For Emma Widmar, diagnosis changed how she lives, but it was not an end. Managing her illness is now her full-time job, but what lingers most is the years spent trying to be believed.
“There’s a huge emphasis on my PTSD because of the way I’ve been treated by healthcare professionals,” she said.
That experience not only forced her to trust her own judgment but also to find meaningful connection and validation outside of a doctor’s office. Online, communities like Reddit and Facebook have thousands of members who share their stories, frustrations, and tips for managing.
But Widmar says sometimes just talking to women in coffee shops or overhearing someone’s circumstances at the grocery store has helped the most.
“It’s always been connecting with others, and that human interaction with others,” she said. “Just because you’re not familiar doesn’t mean that it’s not somebody’s reality,” she added. “Just because someone’s a woman doesn’t mean that they’re having some sort of mental health aspect that is causing their symptoms.”
