Allergies are cause by allergens, often we dont even know the cause of our allergies. It can get irritating as medications does not cure allergy.
Allergy log book logs your allergies like a diary, but better.
It includes location, date, time and trigger (whether allergy happens or not)
After logging multiple entries, hopefully you would be able to point out the cause of allergy from the log patterns.
A special section is also added for medications so as you can log whether symptoms are improving.
The best way to treat allergy is to avoid the allergen all together, provided you know what is it.
Of course, if you can also use this app for other purposes, such as whether what triggers you to become a werewolf.