The diagnosis is by elimination method.
Every day whatever u eat, u write down date time
When u flare up also write down date time.
Over time you will establish which food might be causing it
If not food then is environmental.
Dust is number one possibility. So those bedsheets, carpets, fabric sofa, whatever traps dust is a suspect.
Next is fumes. Anything that emits voc is possible like particle board furniture etc but I suppose not too many at home.
Next is shower gel, shampoo, soap, laundry powder/liquid get the hypoallergenic ones
Then next is any other contact stuffs like your chair u sit in, eg. If false leather etc.