SYMPTOM
Swollen lymph nodes
Owners may observe swollen lymph nodes in their pet.
Various conditions
This symptom can occur in multiple conditions and warrants further assessment.
Why timing matters
Early observation
Early recognition allows prompt assessment and intervention if needed.
Later presentation
Persistent or worsening signs may indicate progression requiring attention.
The significance of this symptom depends on its context, duration, and associated findings.
Conditions commonly associated
Feline Leukaemia Virus (FeLV)
Lymph node enlargement may reflect lymphoma or immune activation from chronic infection.
Lymphoma in Dogs
Lymphoma often causes generalised or localised enlargement of lymph nodes, reflecting the proliferation of abnormal lymphocytes within the lymphatic system. In many cases, the swelling is painless and may be noticed during routine handling or grooming.
Dental Disease in Dogs
Dental disease can lead to enlargement of the submandibular lymph nodes beneath the jaw, as these nodes drain the oral cavity and respond to chronic bacterial presence and inflammation in the gums and teeth.
Dental Disease in Cats
Dental disease in cats may cause swelling of the submandibular lymph nodes due to chronic oral inflammation and bacterial activity, though this finding can be subtle and easily overlooked during routine observation.
Pneumonia
Pneumonia can cause enlargement of the tracheobronchial lymph nodes within the chest as part of the immune response to infection, though these are not palpable externally and tend to be identified through imaging rather than physical examination.
Atopic Dermatitis in Dogs
Atopic dermatitis may occasionally lead to peripheral lymph node enlargement, particularly in areas draining regions of intense inflammation or secondary skin infection, reflecting the immune system's response to ongoing allergic and microbial challenge.
When to explore further
When the symptom is persistent or worsening
When other signs are present alongside
When daily activities or quality of life are affected
When there is uncertainty about the cause
Noting when this symptom occurs, any triggers, and how it changes over time can provide useful information for veterinary discussions.
Last reviewed: 24 April 2026 · Dr Alastair Greenway MRCVS