DEAR MISS MANNERS: I have developed an allergy to shellfish, and it appears that my reactions to it are increasing.

Whereas initially, I just had hives when I’d eat something like shrimp, I can now have a reaction if I’m just sitting near someone who’s eating it.

This is new to me, so I’m trying to navigate the best I can. I strive to be as polite as I can at all times.

If I’m invited to a restaurant, I review the menu online before I go so I know what I’m safe eating. However, someone I’m with might order shellfish, and I can’t tell someone else what not to eat.

I was discussing this with someone yesterday and told them that, if I’m in a group and the dining guest next to me gets shrimp or lobster, I may have to quietly move to another seat. I was told this would be rude, and that I would offend the other guest by moving — even if I gently explained the reason.

But I must. This isn’t a matter of “I don’t like the smell of what you ordered,” but rather, “I could be in the hospital gasping for breath if I don’t get away immediately.”

To counter what some may argue, yes, I do carry an injectable allergy treatment for emergencies. However, the purpose of that is to buy a few moments to get to the ER; it’s not a magical “get out of the situation without any reactions” solution. To stay safe, I need to get some distance from the offending food.

Short of never going out to eat again, I’m not sure what to do. Many restaurants have shellfish on their menus, and I don’t want to be rude and limit what others want to enjoy. I dearly long for lobster and shrimp again myself! But I also don’t feel like having my throat close up and dying.

What’s a Gentle Reader to do that’s acceptable and polite?

GENTLE READER: Normally, Miss Manners asks her Gentle Readers to refrain from discussing their allergies and food restrictions except when specifically asked. But yours is a notable exception.

Warning your dinner companions in advance and offering to research a suitable restaurant is the first step. The next is discreetly informing your server of your situation when you get there so that the kitchen is alerted.

However, if you still fear that there may be shrimp in the air, you may say to a less proximate dinner guest, “Alistair, do you mind switching seats with me? I’m afraid that Margolit’s shellfish might get the better of me and I don’t want to cause a scene.”

DEAR MISS MANNERS: My husband and I pay for tables to various charitable events throughout the year, but never ask our guests to pay. When we are “invited” to an event by friends, we are expected to pay for our seats at the table.

Is this proper etiquette? If not, how do we decline invitations that we have to pay for without offending others?

GENTLE READER: That is what prior commitments are for — even retroactive ones.

Please send your questions to Miss Manners at her website, www.missmanners.com; to her email, dearmissmanners@gmail.com; or through postal mail to Miss Manners, Andrews McMeel Syndication, 1130 Walnut St., Kansas City, MO 64106.