Urticaria could be because if many causes like infection, any food allergy or any tooth caries.. and as u mentioned you are taking Lavetrix m since 2 years, I would recommend you to get
complete blood count done and check for some tooth caries and stop the medication for few days and keep a watch on what type of food you are consuming that is leading to urticaria.. and if there is any precipitating factor I would suggest to avoid that food.. you can send me the reports of your complete blood count, so that we can go ahead with further treatment..
Next Steps
Health Tips
Try to avoid sea food, brinjal and packed food with preservatives