1. Do Your Homework
Most national chains include nutrition information on their websites. These sites often include allergy information. If the restaurant you're thinking of visiting does not have any allergy information available, you may be able to speak to the manager outside of peak business hours to see if they have any allergy information available. Some establishments have separate allergy menus.
2. Avoid Peak Times
You'll be likely to get more attentive service, especially on your first few visits to a given restaurant, if you avoid lunch and dinner rushes. An already harried waiter or waitress will find it more difficult to check on ingredients and answer questions.
3. Make The Waitstaff Your Ally
The waitstaff is your liaison with the kitchen, so be sure to strike up a good rapport.
- Explain your condition thoroughly and let your waiter know that you will have some questions.
- Be polite and acknowledge that you understand that you're requesting additional work on the waiter's part. The implied (or even explicit) promise of additional gratuity may help.
- Make the waiter aware of unusual names your allergen might lurk under. Printing out a list (links below) might be prudent.
- While a pleasant manner is generally the best approach, don't be a pushover. If the waiter is not helpful, ask to speak with a manager.
4. Find Multiple Options
You'll make your life -- and your waiter's! -- easier if you find a few options on the menu so the waiter can ask the kitchen about all of them at once.
Allergy-friendly options on menus fall in two categories: dishes that include no allergens, and dishes that include an allergen as a condiment or side that can be easily removed. In many restaurants, the second category predominates, so consider "what if"s to suggest to your waiter. ("What if the chef made the risotto without cheese?"). Restaurants are not always willing to make accommodations, but in general, the finer the restaurant, the more you can demand.
5. Be Aware of Cross-Contamination
Cross-contamination occurs when food is prepared on a surface or using a utensil that has touched an allergen. You should mention the possibility of cross-contamination to your server so that the kitchen will know to clean utensils and pans thoroughly.
However, two avenues of cross-contamination are difficult to avoid. The first is grills. Ask whether a food marinated in an allergen is cooked directly on the same grill as any grilled dish you might order. The second is frying oil; if you are allergic to something that has been fried in a vat of oil, you should avoid eating anything else fried in that oil.
6. Treasure a Good Relationship
Some restauranteurs will amaze you, even touch you with their willingness to help you. I've frequented restaurants that would happily create wheat-free versions of daily specials and restaurants that would go off menu to create, as much as possible, authentic versions of ethnic dishes that I could eat safely.
Treat these sorts of establishments like you would dear friends or family. Bring them as much business as you can; tell friends about them; thank them sincerely for the service they provide. It's a great pleasure to be able to walk into a café where you know that your medical needs will be attended to.
7. Trust Your Instincts
If you have doubts about your order after you've received it, politely ask your waiter to double-check. Don't be shy or embarrassed about sending food back if indeed a mistake has been made in the kitchen, and be adamant that in the event of a problem like an incorrect side dish that could contain an allergen, you be given an entirely new meal. Simply removing offending items from your plate isn't sufficient to keep you safe. And if at any point you feel that your concerns aren't being taken seriously -- that neither the waitstaff nor the manager are willing to address your concerns -- walk out.
8. Be Prepared
Even under the best of circumstances, it's smart to be prepared for the unexpected. If an allergic reaction would be life-threatening, or even just uncomfortable, bring along whatever treatment your doctor recommends.
Also in the category of being prepared, many restaurants are tolerant of bringing snacks for toddlers and very young children (though not for older children or adults), especially those with medical needs. This can expand your options greatly, as a side dish and a few packed snacks might be sufficient for many children.