Severe long COVID histamine intolerance, somewhat better on Allegra and low-histamine diet
- Condition
- Long COVID
- At worst
- Severe (mostly bedbound)
- Ill before improving or writing
- 3 years
- Last post
- Jul 2025
In their words
- Condition: Long COVID
Got Covid about three years ago, started to become allergic to alcohol.
In context ↗ - At worst: Severe
My symptoms have gotten worse over time and have bred sever for 60 days now.
In context ↗ - Now: Somewhat better
Same thing happened to me minus the severity. ... I have to take Allegra twice a day and eat low histamine diet or I’ll have hives.
In context ↗ - Began after: COVID
Got Covid about three years ago
Summary
A Reddit user who got COVID about three years ago became allergic to alcohol, then after walking pneumonia in 2025 developed histamine intolerance with hives, flushing, red eyelids and floaters, severe for 60 days. Twice-daily Allegra and a low-histamine diet kept hives away; a DAO supplement seemed to help slightly, and a low-histamine probiotic caused flu-like symptoms before settling at 10 billion.
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What they tried
What they credit
Also tried
Their words about each treatment
- keto · Worse
Did keto for like 7 years. Started bingeing and then strict. Off and on and noticed hive like symptoms while strict.
In context ↗ - fasting · Not said
I was doing keto for 5 years, fasting, drinking too much coffee
In context ↗ - eating carbs · Helped
the only thing that stopped these severe symptoms was eating carbs. It stopped the sudden doom feeling and burning in my throat.
In context ↗ - Allegra · Helped
I have been taking Allegra 12 hr twice a day. As soon as the 11 hr hits my symptoms start to come back
In context ↗ - low histamine diet · Helped
The low histamine diet works very well
In context ↗ - DAO supplements · Helped
Yeah, I’m trying that now. It may be working a little bit.
In context ↗ - finasteride · Not said
Was on finasteride.
In context ↗ - low histamine probiotics · Not said
Started low histamine probiotics about two weeks ago and had flue like symptoms bad. Kept on doing it and now it’s fine at 10 billion.
In context ↗
Approaches: H1 antihistamines · Diet
Their path
How ill they were on the ME/CFS severity scale, estimated from what they describe at each point, with time counted from when the illness began. Hover or tap a point. The chart starts 2.5 years after onset: the story doesn’t say how ill they were before that. 1 step says too little to place on the scale and is only in the table. Dates are when they posted. What the levels mean.
Show as a table
| When | What happened | Where they were | After |
|---|---|---|---|
| about three years ago (2022) | got COVID, then became allergic to alcoholGot Covid about three years ago, started to become allergic to alcohol.In context ↗ | Not stated | |
| 2025 | everything worsened after walking pneumoniaThen everything else this year after a bought with walking pneumonia.In context ↗ | Mild | |
| 2025-06-24 | 60 days of severe histamine reactions, hives, redness and flushingMy symptoms have gotten worse over time and have bred sever for 60 days now.In context ↗ | Severe | |
| 2025-06-26 | DAO supplement possibly helping a littleYeah, I’m trying that now. It may be working a little bit.In context ↗ | Mild | DAO enzymes |
| 2025-07-26 | tolerating low-histamine probiotic after a flu-like reaction; still needs twice-daily AllegraKept on doing it and now it’s fine at 10 billion.In context ↗ | Mild |
Adverse events
- Keto and low-carb diets“Did keto for like 7 years. Started bingeing and then strict. Off and on and noticed hive like symptoms while strict.” In context ↗ Allergic reaction / anaphylaxis
- Probiotics and fermented foods“Started low histamine probiotics about two weeks ago and had flue like symptoms bad.” In context ↗ Side effects
Symptoms mentioned
Their words about their symptoms
- Mast cell (MCAS) & allergies
It started with red eyes lids, hives around eyes, some skin flushing, I became allergic to alcohol, and then polyester.
In context ↗ - Headaches & migraine
I tried 1 ounce of cheese this evening and had a really bad headache.
In context ↗ - Vision problems
Like floaters when my symptoms are bad and go away after Allegra
In context ↗ - Anxiety & low mood
It stopped the sudden doom feeling and burning in my throat.
In context ↗ - Flu-like symptoms
Started low histamine probiotics about two weeks ago and had flue like symptoms bad.
In context ↗
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