4 Early Signs That May Signal a Systemic Mastocytosis Flare

When you’re living with systemic mastocytosis (SM), a flare can seem to come out of nowhere. One minute, you feel fine. The next, you’re dealing with diarrhea, hives or even trouble breathing.

But sometimes, your body sends quiet warning signs first, says hematologist-oncologist Aaron Gerds, MD. Learning to recognize those early clues may help you act sooner to help keep your symptoms from getting worse.

What is a systemic mastocytosis flare?

Mast cells are part of your immune system. They release chemicals like histamine to help protect you from allergens and infections. But with systemic mastocytosis, your mast cells can become overactive and release too many chemicals at once. 

That can trigger symptoms throughout your body — known as a flare — which can range from mild to severe.

“You may have something that you know triggers it, or it may be nothing at all,” Dr. Gerds says. “These mast cells can just start to activate and trigger each other.”

Everyone’s flares look different, but they commonly include symptoms that affect your:

• Skin: “Many people with this condition have skin symptoms — namely, little, itchy spots that pop up and then go away,” Dr. Gerds says. This rash is called urticaria pigmentosa.
• Digestive system: “Gastrointestinal symptoms like diarrhea and nausea are common,” he adds. You may also have abdominal pain, cramping, vomiting and/or acid reflux.
• Breathing: In serious cases, flares can lead to anaphylaxis, a life-threatening allergic reaction that requires emergency treatment. Your healthcare provider will likely prescribe you an epinephrine auto-injector to keep on hand.

Early warning signs of a systemic mastocytosis flare

Some people notice subtle physical or emotional changes before the more obvious symptoms of an SM flare kick in.

Knowing these early warning signs can give you a chance to follow your treatment plan early — before a flare escalates and your symptoms get worse.

1. Suddenly feeling ‘off’

For some people, the earliest clue is also the one that’s hardest to describe. It’s the vague sense that something isn’t quite right.

“You may notice feeling very antsy or agitated right before symptoms start to come on,” Dr. Gerds notes.

You may also feel:

• Irritable
• Restless
• Anxious

These symptoms can happen when your mast cells start to release chemicals that affect multiple body systems at once. Even though the other symptoms aren’t obvious to you yet, these feelings can be a sign that your body knows something is going on that shouldn’t be.

2. Flushing or sudden skin changes

Flushing happens when there’s a sudden increase of blood flow to your cheeks, neck or upper chest. It can happen quickly and may feel similar to blushing or overheating. 

“For some people, it’s one of the first signs that mast cells are becoming activated,” Dr. Gerds says.

You may also notice:

• Warmth in your face or chest
• Itchy skin
• Hives
• Red or brown spots that start to become more noticeable

3. Digestive issues

If your gastrointestinal (GI) problems start to ramp up, it could be a sign that a systemic mastocytosis flare is coming on. Flares may begin with:

• Mild nausea
• Stomach cramping
• Bloating
• Loose stools
• A sudden need to poop

“If you have a lot of GI-predominant disease, you’ve likely already made note of which foods are most likely to cause your symptoms,” Dr. Gerds points out.

Avoiding those foods can help you avoid flares. And paying attention to patterns can help you identify any other triggers before your symptoms get worse.

4. A metallic taste in your mouth

Some people report a strange metallic taste shortly before a severe reaction, which Dr. Gerds says can happen before an anaphylactic response develops. It’s part of your body’s early warning system.

“Anaphylaxis is when your airways start to swell and shut down,” he warns. “When this happens, you need an epinephrine injection and emergency care.”

Other early signs of anaphylaxis may include:

• Burning, tingling or itchiness in your mouth
• A burning sensation in your hands and feet
• A headache that comes on quickly
• Suddenly feeling afraid or confused

Your healthcare provider will explain to you when and how to use your epinephrine injector in case of anaphylaxis. And even if your symptoms improve after using epinephrine, you still need emergency evaluation.

When should you seek emergency care?

Some symptoms require immediate medical attention. Call 911 or seek emergency care if you experience:

• Trouble breathing
• Wheezing
• Swelling in your throat or tongue
• Chest tightness
• Dizziness or fainting
• Severe hives or flushing
• Symptoms of anaphylaxis

And it’s important enough that we’ll say it again: Even if your symptoms get better after you give yourself an epinephrine injection, you still need to be evaluated by a healthcare provider ASAP.

How to track systemic mastocytosis symptoms

It can take a long time to receive a diagnosis of systemic mastocytosis. By the time you finally get a name for what you’re going through, you likely already know what some of your triggers are — because you’ve been doing your best to avoid them.

“People with this condition often understand or work through things on their own over time,” Dr. Gerds acknowledges. “They’re often able to figure out what types of exposures seem to bother them most.”

Still, because symptoms can vary so much, tracking your experiences may help you recognize patterns over time. Consider keeping notes about:

• Symptoms
• Foods
• Stress levels
• Environmental exposures
• New products, like detergents and lotions
• Timing of flares

You may discover patterns you hadn’t noticed before, which you can share with your provider to help guide your treatment plan.

“There are approved therapies that can dramatically reduce symptoms and lower the risk of flares,” Dr. Gerds encourages. “At the end of the day, the flare that you don't have is the most important one — because it means we were able to prevent it from happening.”