I too am  teacher in a public school system.  Children in public schools
are protected from discrimination by federal ADA and IDEA regulations.
In most cases you will need to have a written diagnosis regarding the
disabling factor in order to receive service.

We had to document our child's anaphylactic milk allergic reactions to
complete a 504 plan with the school district.  It is a long involved
story on our part in which we had to educate some people who did not
want to understand the severity of her medical requirements or the legal
mandates regarding disabilities and civil rights of children or anyone
with allergies.  This probably won't be an issue in daycare but you will
have the documentation you might need later for kindergarten, etc.

In addition, you might want to think about a step by step plan of what
must be done in the classroom to protect your child (no crafts with milk
cartons, for example) AND a plan for what to do in an emergency
situation or accidental ingestion.

Bear in mind that you should keep copies of all of those forms and
letters from your child's doctor for your home files.  You might need
them for some other event or activity such as a boy scout camp or sleep
over with a friend, etc.  Having written protocol and forms are helpful
to people unfamiliar with your child.

In addition to all the forms that I supply to all the teachers who have
contact with my child, I also have prepared a small basic emergency
information tag on the backpack that goes everywhere my child goes.  If
something happened to my husband or myself-- say a car accident--  she
would hopefully be cared for adequately due to her info tags and Medic
Alert bracelet.

Many people on this list serv were helpful when I was preparing these
information items.  You will be helped here too.

Good luck :)
Deborah