POTS, EDS and MCAS Trifecta: Which One Is the Real Problem?

Why Do POTS, EDS and MCAS Show Up Together?

A 2026 systematic review concluded that EDS and POTS frequently co-occur, with proportions that depend on the population studied (Kwok, 2026). Most of the triad research is about hypermobile EDS (hEDS), the type diagnosed by exam, so that's the type this page means by EDS. The mast cell link has less behind it. A 2020 review of all 3 conditions found that "a real relationship between these entities is unclear due to a lack of scientific validity," and none of the papers it found came from searching the 3 together (Kucharik, 2020).

In 2026, 2 papers questioned the MCAS link in their titles. A research letter is titled "Lack of evidence for increased mast cell activation syndrome prevalence in postural orthostatic tachycardia syndrome and/or hypermobile Ehlers-Danlos syndrome" (Valdez, 2026), and a review of EDS and MCAS asks, "Is there scientific evidence?" (Cuenca-Gómez, 2026). Finding the 3 together says nothing yet about which one, if any, causes the others. POTS and EDS: why they show up together covers the proposed mechanisms.

How Do You Tell Which One Is the Real Problem?

In our team's experience, when you check everything, nearly anyone turns up something, and it's hard to know how much weight each finding deserves. Our team doesn't use fixed if-then rules to sort the 3. We ask what the boundary conditions are: which factors shape how you function the most, and whether solving them lets the system work better even while the other conditions are still there.

For each diagnosis, the question is whether it's causing the problem or contributing to it. In our team's view, the sorting rule follows from that: find the problem that, once solved, changes the course of the others, and put the most energy there first.

Is the Immune Side Leading?

In our team's view, a flare that hits the skin, throat and gut at the same time raises the question of whether something global, including the nervous system's control, is involved, while a reaction tied to one trigger suggests a more local cause. In our team's view, an allergist can test the mast cell side.

In our team's view, an allergist can test the mast cell side, and it helps to see whether your levels are actually abnormal before intervening.

Can an Infection Look Like POTS?

In our team's view, a gut infection such as SIBO or H. pylori may bring a racing heart and dizziness on standing that look a lot like POTS, because the body may step up blood flow to fight it off. A fever is the familiar version: your heart beats hard and fast, you sweat, and you're dizzy when you stand. If the autonomic problems are still there after the infection is treated, the cause may run the other way, and the autonomic side is the one to address.

In POTS, our team reads the high heart rate as a compensation that protects blood flow to the brain, so the heart rate alone can't say which side started it. What's left after one side is addressed can hint at which side was leading.

Immune side leading Autonomic side leading

Replay

Where Does Hypermobility Fit In?

There's no blood test for hEDS, so the diagnosis rests on examining how a person moves. Our team also sees people who meet the flexibility criteria and feel fine, which is why we count hypermobility as a possible contributor before calling it the cause.

In our team's view, the people who check joint looseness and the people who judge muscle tone often work in different specialties, and the criteria lean toward the hypermobility model. Our team checks whether low muscle tone comes with the flexibility, as covered in hypermobile EDS treatment: rule out low tone first.

How Are POTS, EDS and MCAS Treated Together?

There's no single treatment for all 3. In our team's view, an allergist can test the mast cell side (see how MCAS and POTS are treated when both are present). Our team's work is on the autonomic side: testing how the brain regulates heart rate, blood pressure and brain blood flow. We don't treat connective tissue or joint laxity. For one person with both, see one patient's EDS and POTS case.

POTS, EDS and MCAS: FAQ