Pyrexia in Dogs: Causes, Symptoms and Care Guide

Pyrexia in dogs is the medical term for a fever, where a dog's body temperature rises above the normal range, typically between 99.5#6F and 102.5#6F (37.5#6C to 39.2#6C). When temperatures reach 103.5#6F (39.7#6C) or higher, it is considered a fever indicating an underlying health issue that requires timely veterinary attention.

What Causes Pyrexia in Dogs?

Fever is rarely the primary disease; instead, it signals an underlying cause that the body is trying to fight. Commonly, pyrexia is a natural immune response to viral, bacterial, or parasitic infections, as the dog's body raises its temperature to limit bacterial growth and boost immune response. Other causes include immune-mediated diseases, tumours, metabolic or endocrine disorders, inflammatory conditions, reaction to medications, contact with toxins, or unknown causes categorised as Fever of Unknown Origin (FUO).

Recognising Symptoms Associated with Pyrexia

• Elevated body temperature beyond normal range
• Shivering or chills
• Weakness or lethargy
• Loss of appetite
• Rapid heart rate
• Dehydration signs such as dry gums
• Rapid or laboured breathing
• Possible signs of shock in severe cases

Diagnosing the Underlying Cause

A veterinary examination is crucial when your dog has a raised temperature, especially if it persists beyond four days. The vet will take a detailed history and recommend diagnostic tests including a complete blood count, biochemistry panel, urinalysis, and imaging like X-rays, ultrasound, CT or MRI scans. In some cases, endoscopy might be necessary to investigate internal obstructions or infections. These investigations help identify the exact cause and guide targeted treatment.

Treatment Based on Cause

Treatment depends on the underlying condition found by the vet. For example, bacterial infections require a full course of antibiotics, which must be completed even if symptoms improve early on. Dogs severely dehydrated from fever may need hospitalisation with fluid therapy and close monitoring. If no cause is detected (FUO), referral to a veterinary specialist may be suggested, although these advanced diagnostics can be costly and invasive.

Aftercare and Recovery

The recovery phase is just as important. Limit your dog's exercise to avoid stress while the immune system recovers. Provide a balanced, nutritious diet with sufficient calories to support healing. If the dog refuses to eat solid food, the vet might recommend a high-calorie liquid diet temporarily. Keeping your dog comfortable, hydrated, and stress-free supports a timely recovery.

Why Dogs Develop Pyrexia of Unknown Origin (PUO/FUO)

Quick Answer: Pyrexia of Unknown Origin refers to a persistent fever lasting more than four days without an identifiable cause after thorough veterinary diagnostics.

Occasionally, despite comprehensive testing, no clear cause of fever can be found. This is called PUO or FUO. It can be frustrating for owners but requires collaborative veterinary approaches including repeated assessments and sometimes empirical treatments. Causes in PUO can range from hidden infections to immune disorders or inflammation not easily detected by routine tests.

How to Check Your Dog’s Temperature at Home

Measuring your dog's temperature at home can help detect pyrexia early. Use a digital rectal thermometer and lubricate it with petroleum jelly. Gently insert the thermometer about one inch into your dog's rectum and wait for the reading. Normal temperature range is 99.5#6F to 102.5#6F. A reading above this requires veterinary advice promptly, especially if accompanied by other symptoms.

Common Questions About Dogs and Fever

Can I give my dog Calpol for fever?

Human medications like Calpol (paracetamol) are not safe for dogs and should never be administered. Always seek veterinary guidance to ensure safe and effective treatment options.

When is a dog’s temperature considered dangerously high?

Temperatures above 41#6C (105.8#6F) are potentially life-threatening and require emergency veterinary care.

How quickly should I seek veterinary care if my dog has a fever?

If your dog has an elevated temperature for more than 24 hours, or shows other signs like lethargy and loss of appetite, contact your vet promptly.

Conclusion

Pyrexia in dogs is a vital sign alerting owners and vets to potential health issues. Prompt veterinary investigation and treatment are important to address the underlying cause effectively. With appropriate aftercare, most dogs recover well from episodes of fever. Always work closely with your vet to safeguard your dog's health—avoiding self-medication and ensuring comprehensive support through diagnosis and treatment.