Janet the 1-year-old rescue Guinea pig suddenly developed a swelling underneath her jaw. Although she seemed well in herself Janet’s owner knew that it was important to get her checked over by a Guinea pig savvy vet. 

The chin and neck are common places for Guinea pigs to develop lumps, so it’s a good idea to regularly check this area at home with a good chin rub when stroking them. On clinical exam she was otherwise well but tender around this swelling. There are a lot of different potential causes for lumps in this area such as: Dental disease, foreign bodies, infections, cysts, salivary gland disease, and even tumours.

With Janets young age and how quickly the swelling appeared we suspected an infection causing an abscess. In her first consultation we were able to confirm this by gently using a needle and syringe to draw out pus from the swelling after we had numbed the area. This also helped to relieve some of the pressure and discomfort of the swelling.

Knowing that the lump was an abscess was only half of the story; we knew an infection was present, but we didn’t know what had caused it.  Antibiotics and anti-inflammatories alone often do not completely clear up abscesses in Guinea pigs. They are very good at walling off infection with a thick capsule so that they don’t feel unwell in the rest of their body, but this also provides a good hiding spot for bacteria to stick around in. Bacteria can also hide in tooth roots, lymph nodes and foreign bodies, so although medication might help initially, the abscesses can often return or never completely clear up. Some form of surgery is usually required to cure these abscesses.

Under a general anaesthetic we x-rayed her head and could see that the abscess was being caused by an infected tooth root. The jaw had also reacted to the infection by producing some extra bone which looks like a thin bubble of bone on the lower jaw. With some delicate surgery we were able to completely remove the infected tooth and performed a procedure called marsupialisation – making an open pouch by suturing the inside of the abscesses capsule wall to the edge of her skin allowing the abscess to drain. The abscess can then heal cleanly without the risk of closing up and trapping the infection again. 

Surgery was a success; Janet was eating immediately after her GA and much happier to be without her nasty toothache. 

Next time you give your Guinea pigs a chin tickle remember to check for lumps. We also recommend routine 6 monthly health checks with a vet for all species to pick up any subtle health changes before they become a problem.

Amy Bowler – BVSc PGCert (ExAS) MRCVS RCVS Advanced Practitioner in Zoological Medicine