Relapse

The term relapse refers to the recurrence of a disease or symptom – specifically after a phase in which the dog seemed to have improved again. This is confusing and frustrating for many owners: You think the matter is over, and then the problem reappears. Why does this happen? The reasons are multifaceted – from treatment that was too short through chronic pre-existing conditions to genetic predisposition.

What is a relapse?

A relapse occurs when a disease or symptom reappears after an apparent recovery. This can happen immediately after the first episode – or only weeks, months, sometimes even years later. Basically, a relapse indicates that the disease was never truly fully overcome or that the actual cause continued to smoulder hidden away.

Two classic examples from veterinary practice: A tumour that returns at some point after successful surgery. Or an ear infection that initially subsides after treatment – and then flares up again.

Causes of a relapse in dogs

Why does a disease return even though it was treated? There are several answers to this, and they do not exclude each other:

1. Undiagnosed underlying condition and too short therapy: Both are considered the most common causes in recurring bacterial pyoderma, i.e. the overlooked triggering underlying problem as well as antibiotic treatment that was dosed too low or given for too short a period. Therapy should be continued until skin changes have healed completely and the follow-up examination shows no further infection.
2. Chronic underlying conditions: With conditions such as arthritis, heart disease or diabetes, flare-ups are almost part of the clinical picture. These conditions can generally not be cured, but only managed long-term – which structurally increases the risk of recurrence.
3. Unfavourable ear anatomy: Floppy pinnae, narrow ear canals and a heavily haired pinna are among the risk factors for otitis externa; the ear canal should remain dry and well-ventilated.
4. Immunosuppression: A weakened immune system – due to advanced age, corticosteroids or a condition such as cancer – makes the body more susceptible. It can simply keep infections under control less effectively, making relapses more likely.
5. Environmental factors and allergies: Pollen, mites, stress, parasites – all of this can trigger recurrences. A dog with a pollen allergy develops seasonal skin or respiratory problems again and again as long as the trigger does not disappear from its environment.

Common diseases with recurrences in dogs

Some conditions are significantly more prone to relapse than others. If you have a dog with one of the following diagnoses, you should keep this in mind:

1. Tumours and cancer: Particularly with malignant tumours, a tumour recurrence can occur after successful treatment – either at the original site or in other organs. The cause is often cancer cells that have survived surgery or radiotherapy.
2. Otitis (ear infections): Especially in breeds with long, floppy ears, inflammation is a constant issue. The underlying cause must be addressed to prevent a relapse; primarily the primary causes must be treated so that otitis externa does not persist or recur.
3. Skin infections (pyoderma): The most common underlying conditions causing superficial pyoderma in dogs are ectoparasites, allergies such as atopic dermatitis, food allergy and flea bite allergy, as well as hormonal disorders such as hypothyroidism and Cushing’s syndrome. Without treatment of the underlying cause, pyoderma returns.

Diagnosis of a recurrence

Before speaking of a recurrence, the vet must rule out that it is a completely new condition. This usually requires more effort than the first time:

1. Clinical examination: The vet thoroughly examines the dog and checks whether the current symptoms match the previous clinical picture.
2. Blood tests and laboratory examinations: Blood count, urine or faecal analysis – depending on suspicion. These tests help to detect infections, inflammatory markers or metabolic disorders.
3. Imaging techniques: If a tumour is suspected, X-rays, ultrasound or computed tomography (CT) are used to narrow down the location and size of possible changes.
4. Biopsy: In the case of tumour recurrence, a new tissue sample may be necessary – to clarify whether it is the same tumour or a new occurrence.

Treatment of a recurrence

How a recurrence is treated depends heavily on the underlying condition and the severity of the relapse. The range is wide:

1. Treatment until proven endpoint: With bacterial skin infections, therapy should be continued until the skin changes have healed completely and the follow-up examination no longer shows an infection; the choice of antibiotic is based on culture and susceptibility testing.
2. Surgery: In the case of tumour recurrence, a new operation may be necessary. Sometimes more tissue must be removed than in the first procedure to ensure that no cancer cells remain.
3. Long-term therapy: Chronic conditions such as diabetes, arthritis or thyroid problems require permanent support. A cure is often not possible, but with medication and adapted nutrition, much can be well controlled.
4. Immunotherapy and radiotherapy: For recurring tumours, these options can be used additionally to combat remaining cancer cells or to specifically strengthen the immune system.
5. Environmental adjustments: With allergies or recurring respiratory problems, it is worth taking a critical look at the dog’s environment. Less contact with pollen, house dust mites or other allergens, possibly an air purifier or hypoallergenic food – such measures can make the difference.

Prevention of a recurrence

Relapses cannot always be prevented entirely. But the risk can be noticeably reduced with some consistent measures:

1. Complete treatments fully: Give medication for as long as the vet recommends – even if the dog already seems lively again. Stopping early is one of the most common mistakes.
2. Regular check-ups: Dogs with known susceptibilities should be presented to the vet regularly. Early signs of a relapse can be treated much better than advanced ones.
3. Avoid triggers consistently: Keep known allergens out of the dog’s daily life as far as possible. With a weakened immune system, also reduce contact with potential pathogens.

Conclusion

A relapse is not a failure – neither of the vet nor of the owner. It shows that some conditions are more stubborn than a single treatment might suggest. The causes range from a therapy that was too short to chronic underlying diseases that simply cannot be eradicated once and for all. Those who look early, treat consistently and visit the vet regularly can still secure their dog’s well-being in the long term – and significantly reduce the frequency of relapses.