Connie Hall answered question 9/6/2008 Why Are My Dog's Testicles Shrinking? He Is At Present Taking Antibiotic And Anti-allergy Pills. The Vet Said He Has Skin Problems. He Is An 8-year-old Pekingese. Are The Pills Causing The Shrinking Of His Testicles? I would take him to another Vet & get a second opinion. Vets some times makes mistakes too.