Built for MCAS

Track every symptom.
Find every trigger.

Log reactions in seconds, uncover hidden patterns, and finally understand what's driving your flares — free, on every device.

100+ trackable symptoms
4.8 ★ App Store rating
Free no paywalls, ever
MastCell Tracker — Daily symptom log
Symptom Logging
Pattern Analysis
Trigger Identification
Calendar View
Doctor Reports
Privacy First
Works Offline
PDF Export
Medication Tracker
Emergency Access
Symptom Logging
Pattern Analysis
Trigger Identification
Calendar View
Doctor Reports
Privacy First
Works Offline
PDF Export
Medication Tracker
Emergency Access

Every tool you need,
built for MCAS.

01
Daily Logging

Log any reaction
in under 10 seconds.

Custom severity scales, free-text notes, timestamps, food logs, and environmental factors — all captured the moment it happens, even without signal.

Severity scale Timestamps Free-text notes Works offline
Daily symptom logging screen
Calendar and pattern view
02
Calendar & Patterns

See your full history
at a glance.

Visual calendar mapping of every logged reaction. Instantly see your best days, your worst, and what changed — then export it all for your next appointment.

Calendar view Trend analysis AI pattern detection PDF export
03
Emergency Access

Critical info, one tap,
no signal needed.

Your emergency action plan, medications, allergies, and emergency contacts — always accessible offline. Because MCAS emergencies don't wait for WiFi.

Fully offline Emergency contacts Medications list One-tap access
Emergency access screen

Built for the real
world of MCAS.

Three screens. Every situation. Designed to be there whenever a reaction hits — wherever you are.

Calendar view
Calendar View
Daily log
Daily Log
Emergency access
Emergency
100+
trackable symptoms
and triggers
4.8★
App Store rating from
verified patients
Free
No subscription, no paywall,
no data selling
Possible correlations
surfaced automatically

Everything you'd expect,
and things you didn't know you needed.

Download the app →
📋

Symptom Logging

Log reactions in seconds with custom severity scales, free-text notes, and timestamps. Never miss what happened or when.

📈

Pattern Analysis

Visualize your symptom history over days, weeks, and months. Spot trends you'd never catch from memory alone.

🔍

Trigger Identification

Track foods, environments, activities, and medications alongside symptoms to pinpoint what sets off your reactions.

🗓️

Calendar View

Your full symptom history mapped to a calendar. Instantly understand your good days, your bad days, and what changed.

📄

Doctor-Ready Reports

Export a clean PDF summary of your symptom history formatted for clinical appointments — so every second counts.

🚨

Emergency Access

One-tap emergency info — medications, allergies, contacts — always available offline. Because reactions don't wait for signal.

See why MCAS patients
trust MastCell Tracker

Real words from patients, caregivers, and clinicians who use it every day.

S
Sarah M.
MCAS patient, diagnosed 2019
"I've tried every health app out there. None of them understood what it's like to live with MCAS — the random triggers, the unpredictable flares. MastCell Tracker is the first one built for us. I finally feel like I have real data to bring to my doctor."
J
James R.
Caregiver & MCAS advocate
"My daughter has severe MCAS and keeping track of her reactions used to take a spreadsheet, a notebook, and a lot of guesswork. We identified her three worst food triggers within the first month."
M
Maya T.
MCAS + EDS community member
"The offline mode is everything. I react in restaurants, parks, gyms — places with no signal. Logging a reaction the moment it happens means my data is actually accurate."
L
Dr. Lauren K.
Allergist & immunologist
"The PDF reports patients bring to appointments give me a clearer picture in five minutes than months of informal notes. It's made a real difference in how quickly we can refine treatment."

Everything you need
to manage your MCAS

Get the app — it's free

See how patients are tracking and understanding their MCAS

Patient stories

Building better habits for chronic illness tracking

From our team

Get started with MastCell Tracker — free on iOS and Android

Download now