Eltroxin and Shellfish Allergy

My Daughter is 4 years old. She was diagnosed with Hypothyroidism at the age of 3 months and receives a small daily dose of Eltroxin to supplement her own thyroid production. She recently had a very severe allergic reaction to some shellfish (prawns) that she ate. Her face swelled terribly and her left eye was swollen closed. She need antihistamine treatment to relieve the swelling. Could the allergy have anything to do with her condition or her treatment?

[Mark Lupo, M.D.]

Probably coincidental - would not change eltroxin unless reaction persists - then may need to change brand or dose (ie dye).