Thanks for your query. Brief answer: Yes,you can take any of the antihistamines(Loratadine/desloratadine/fexofenadine ) to relief your current symptoms of allergy. Detailed answer:I understand that you are very much affectionate towards your puppy.You are talented enough that you have found out the cause of your allergy. Many allergens are found in animals’ hair, saliva, urine, stool and shed skin. The best treatment for allergy is to avoid allergen or its source if possible. If your allergy is due to puppy, I would request you to keep a distance from it. Otherwise it may create other health problems like asthma in future. Antihistamine is useful to relief symptoms but long term use of a medicine is hardly rational. Hope this answers your query. Wish you good health.