Diarrhea: Diarrhea is one of the manifestations of enteritis or gastroenteritis. There are many types of enteritis, including parasitic, infectious, food allergy or intolerance, sudden dietary changes, and stress. Experienced veterinarians can distinguish causes such as small intestine inflammation, large intestine inflammation, and exocrine pancreatic insufficiency through tests.　　　　Constipation: Clinical causes of constipation include: cats swallowing loose hair during grooming due to backward barbs on the tongue, which mixes with intestinal contents causing blockage; ingestion of large bones or foreign objects; lumbar vertebra disease; anal sac enlargement; rectal stenosis; intestinal tumors; perineal hernia; prostatitis; and megacolon in elderly dogs and cats.
　　　　Bloody stool: Bloody stool is primarily caused by intestinal bleeding. When bleeding occurs in the small intestine, stool appears dark red, while bleeding in the large intestine causes bright red stool, sometimes with blood streaks. Hemorrhagic enteritis is usually associated with parvovirus, intussusception, hookworms, and coccidia, but can also be seen with tapeworms, severe roundworm infestation, ingestion of sharp foreign objects, and severe anal gland inflammation.　　　　Hair loss: Under normal circumstances, dogs and cats shed hair seasonally in spring and autumn.
Abnormal hair loss can be due to the following conditions: skin diseases, excessive bathing, using human shampoos, or symmetrical hair loss caused by endocrine disorders in dogs and cats.　　　　Skin rash: Rashes are mainly caused by mites, bacteria, fungi, allergies, and drug rashes. Laboratory testing is needed for diagnosis.　　　　Peeling: Peeling occurs due to excessive bathing, use of alkaline shampoos, fungal infections, unusual skin irritations, and certain metabolic diseases.
　　　　Itching: Itching is caused by puppy pyoderma, sarcoptic mange, demodectic mange with secondary bacterial infections, allergies, external parasite bites, foreign body irritation, and abnormal hormone secretion.　　。