MCAS. Reactions, sorted by severity and system.

Mast cell reactions hit different systems at different intensities — skin, gut, airway, heart. Leo's MCAS hub sorts each reaction by severity tier and body system, splits food from environmental triggers, and pairs with a food diary so the safe-and-unsafe picture builds itself.

Status · in app today·Tracking · reactions + food diary·Photos · none, ever
Built for MCAS

Every reaction, placed on a severity scale.

Reactions are sorted into four tiers — mild, moderate, severe, anaphylactic — and broken down by body system (skin, GI, respiratory, neurological, cardiovascular), with a four-week frequency trend so escalation is visible.

Trigger analysis splits food from environmental, and a food-safety profile surfaces your high-risk and watch-list foods from what you've logged — paired with a food diary that prompts a follow-up after meals.

What you track

Reactions, triggers, and food safety.

Reaction severity

Mild, moderate, severe or anaphylactic — every reaction placed on the scale, with the distribution at a glance.

Severity tiers

Body systems

Skin, GI, respiratory, neurological and cardiovascular — see which systems your reactions target.

System breakdown

Food diary

Log meals with a post-meal follow-up, so delayed reactions get connected to what you ate.

Food diary

Food safety

Your high-risk and watch-list foods, surfaced from what you've logged over time.

Safety profile

Trigger analysis

Food vs environmental split, plus a four-week reaction-frequency trend.

Trends

Labs

CBC, CMP, inflammatory, iron, liver and vitamin D come pinned, with trends and ranges.

Pinned labs
Hub at a glance

What ships in the MCAS hub.

Reaction severity distribution — mild, moderate, severe, anaphylactic
Body-system breakdown of where reactions land
Food diary with post-meal follow-up
Food-safety profile — high-risk and watch-list foods
Trigger analysis: food vs environmental + four-week trend
Recent reactions with severity badges
Pinned labs — CBC, CMP, inflammatory, iron, liver, vitamin D
Honest scope

Leo tracks. It doesn't diagnose.

MCAS is diagnosed by a clinician with specific lab and response criteria — Leo has no screener and makes no claim about whether you have it. It is not an allergy test and is not a substitute for an epinephrine plan.

Everything is descriptive and on-device-first. The severity tiers and food-safety profile describe what you logged; they never predict a reaction or give medical advice.

MCAS hub

Reactions and triggers, on the record.

Reactions sorted by severity and body system, food vs environmental trigger analysis, and a food-safety profile from your own logs — organized for your immunologist or allergist.