Dogs are like infants they can't tell their problem. You touch the dogs nose and the back of ears and notice the temperature, in fever it would be warmer, but a thermometer is preferred. The normal body temperature is 102 F. Itching and vomiting are also the symptoms. For more info click here.
Average temperature on a dog is 101 degree Fahrenheit, and 38 degree Celsius. The normal temperature can vary a few degrees either way, 99-102.5 F, or 37.2-39.2 C.
If you know how warm your dog usually feels, you can put your hand on the inside of it's ear, and if it feels unusually warm then it could have a fever. To confirm, get a rectal thermometer. You might need someone to help you with this, as dogs don't usually like this procedure. If you're using a mercury thermometer, make sure the mercury is below 94 degrees. Lubricate it with petroleum jelly, or other water-based lubricant. Have the other person hold the dogs head and front part of body by tightly hugging the dog to stop it moving. Lift the tail, and insert the thermometer slowly into the rectum. Insert it about 1 inch, and hold it in place for two minutes, or if you're using a digital one, until it beeps. Remove, and read the temperature.
You can not tell about fever in dogs without use of thermometer. You can only suspect fever in dogs by noting some signs like loss of appetite and lethargy etc but can not confirm. When rectal temperature in dogs is over 103 F then he is having fever. Dry and warm nose in dogs don't tell about fever. Fever in dogs can be due to
1. Bacteria or viral infection 2. Ticks bite 3. Immune system disease 4. Cancer 5. Tapeworm 6. Heartworm
So, for diagnosis and treatment of fever in dogs, get vet help.
