Dehydration occurs when a dog loses body fluids faster than he can replace them. Dehydration usually involves the loss of both water and electrolytes. In dogs, the most common causes of dehydration are severe vomiting and diarrhea. Dehydration can also be caused by inadequate fluid intake, often associated with fever and severe illness. A rapid loss of fluids also occurs with heat stroke. A prominent sign of dehydration is loss of skin elasticity. When the skin along the back is pulled up, it should spring back into place. In a dehydrated animal, the skin stays up in a ridge. Another sign of dehydration is dryness of the mouth. The gums, which should be wet and glistening, become dry and tacky. The saliva is thick and tenacious. In an advanced case, the eyes are sunken and the dog exhibits signs of shock, including collapse.
Treatment: A dog who is visibly dehydrated should receive immediate veterinary attention, including intravenous fluids, to replace fluids and prevent further loss.
For mild dehydration, if the dog is not vomiting you can give him an electrolyte solution by bottle or syringe into the cheek pouch (see How to Give Medications). Balanced electrolyte solutions for treating dehydration in children, such as Ringer’s lactate with 5 percent dextrose in water or Pedialyte solution, are available at drugstores and are also suitable for dogs. Gatorade is another short-term substitute to help replace fluids. Administer the solution at a rate of 2 to 4 ml per pound (1 to 2 ml per kilo) of body weight per hour, depending on the severity of the dehydration (or as directed by your veterinarian).