Cervical lymphadenitis in guinea pigs — commonly called "lumps" — is a bacterial infection of the lymph nodes in the neck, usually caused by Streptococcus zooepidemicus. The hallmark is one or more firm to soft swellings along the underside of the jaw and neck. Treatment is surgical removal of the affected lymph nodes plus a long course of safe antibiotics. Most pigs recover well when caught early.
Last reviewed: May 2026
What Is Cervical Lymphadenitis in Guinea Pigs?
Cervical lymphadenitis in guinea pigs, often informally called "lumps," is a bacterial infection of the cervical (neck) lymph nodes. The most common cause is Streptococcus zooepidemicus, which enters through small breaks in the mouth (caused by hay scratches, sharp tooth edges, or dental disease) and travels via lymphatic drainage to the submandibular lymph nodes. Less commonly, other bacteria including Streptococcus pneumoniae, Staphylococcus aureus, or Pasteurella are involved.
The condition occurs in pigs of any age but is most common in young to middle-aged animals. Stress, overcrowding, and poor husbandry are risk factors. Pigs in a stressed or immune-compromised state can become carriers of S. zooepidemicus without showing signs, then develop disease when conditions favor it, as described in Quesenberry and Carpenter's Ferrets, Rabbits and Rodents.
How to Recognize It
The classic presentation is one or more firm, slowly enlarging lumps along the underside of the jaw, neck, or upper chest. Early lumps may be the size of a marble; they can grow to plum-size or larger over weeks. As the abscess matures, the lump softens, develops a thin overlying skin, and may eventually rupture spontaneously, draining thick white-yellow pus.
Most affected pigs initially eat and act normally, which is one reason owners delay vet visits. As the disease progresses or if airway compression occurs, decreased appetite, difficulty swallowing, weight loss, and lethargy develop. Approximately 60 to 80 percent of pigs with cervical lymphadenitis are systemically well at presentation but require treatment to prevent progression.
How Vets Diagnose
The diagnosis is largely clinical based on location and appearance, supported by fine-needle aspiration of the lump showing degenerate neutrophils and bacteria. Bacterial culture and sensitivity from aspirated pus or surgical samples guides antibiotic choice. Bloodwork helps assess overall systemic health. Radiographs or ultrasound may be done to evaluate the depth of involvement and rule out other lumps in the chest.
Differential diagnoses include cysts, abscesses from other causes, neoplasia (lymphoma is uncommon but possible), and dental disease with secondary swelling.
Treatment Approach
The treatment of choice is complete surgical removal of the affected lymph node or nodes (lymphadenectomy) under general anesthesia, followed by a prolonged course of safe antibiotics for 4 to 8 weeks. Surgical removal of the whole infected capsule provides much better long-term outcomes than simple lancing and drainage, which has a high recurrence rate.
Safe antibiotic choices for guinea pigs include trimethoprim-sulfa, enrofloxacin, chloramphenicol, and azithromycin. Nutritional support with high-fiber hay, vitamin C, and recovery formula follows established nutrition guidance (WSAVA Global Nutrition Guidelines, 2011). Penicillins, lincomycin, clindamycin, and erythromycin are dangerous and can cause fatal enterotoxemia in guinea pigs by disrupting normal gut flora. Pain control with meloxicam at appropriate dose, supportive nutrition (Critical Care syringe feeding if appetite drops), and warm housing aid recovery (AEMV Pet Care Guides, 2024).
Prognosis
Most guinea pigs recover well from cervical lymphadenitis when treated with surgery plus appropriate antibiotics. Long-term recurrence after surgical lymphadenectomy is approximately 10 to 20 percent. Pigs treated only with drainage or antibiotics without surgery have higher recurrence rates of 30 to 50 percent or more. Concurrent dental disease should be addressed at the same anesthesia to remove a potential entry source for future infection.
When to See a Vet
Not every symptom is a midnight emergency, but some warrant same-day attention and a few are true ERs. Use the lists below to sort which bucket you're in.
Call your exotic vet today if:
- New firm lump along the underside of the jaw, neck, or upper chest
- Slowly enlarging swelling that has been present for more than a few days
- Mild decrease in appetite or selective eating
- Visible head or neck holding in an unusual position
- Soft fluctuant lump (suggests abscess maturation)
Go to the ER immediately if:
- Rapidly growing neck swelling with breathing difficulty
- Complete refusal to eat for more than 12 hours
- Severe lethargy, weakness, or cold ears
- A ruptured lump with active drainage and the pig is systemically unwell
- Hunched posture, tooth grinding, or vomiting
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Frequently Asked Questions
How much does cervical lymphadenitis treatment cost?
Initial diagnostic workup with exam, fine-needle aspirate, culture, and bloodwork typically runs $250 to $500. Surgical lymphadenectomy with anesthesia and dental exam runs $500 to $1,500 depending on the number and size of nodes involved. Post-operative antibiotic and recheck costs add $80 to $200 per month for 1 to 2 months. Hospitalization for severely affected pigs adds $300 to $800 per day.
Is this infection contagious to my other guinea pigs?
Streptococcus zooepidemicus can be carried asymptomatically by many guinea pigs and can transmit between cagemates, especially under stress or in crowded conditions. Cagemates of an affected pig should be examined and ideally separated until treatment is well underway. Good husbandry — clean dry bedding, adequate space, low stress, vitamin C supplementation — reduces the chance of an outbreak.
Why can't you just give antibiotics without surgery?
Without surgical removal of the infected lymph node, antibiotics alone struggle to fully penetrate the thick fibrous capsule and dense pus that characterizes guinea pig abscesses. Recurrence rates with antibiotics alone are 30 to 50 percent or higher. Surgery plus antibiotics gives the best long-term outcome and the shortest course of medication.
What antibiotics are dangerous for guinea pigs?
Penicillins (amoxicillin, ampicillin, penicillin), lincomycin, clindamycin, erythromycin, vancomycin, and some cephalosporins are toxic by mouth to guinea pigs — they disrupt normal gut flora and cause fatal enterotoxemia. Safe options include trimethoprim-sulfa, enrofloxacin, marbofloxacin, chloramphenicol, azithromycin, and doxycycline. Always confirm with an exotic vet before giving any antibiotic to a guinea pig.
Could the lump be cancer instead?
Lymphoma and other neoplasms do occur in guinea pigs but are far less common than abscesses in the neck. Fine-needle aspiration cytology usually distinguishes bacterial abscess (degenerate neutrophils and bacteria) from neoplasia (atypical lymphocytes or tumor cells). When in doubt, biopsy and histopathology give a definitive answer.
Still Not Sure if Your Guinea Pig Needs a Vet?
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