TL;DR: Swollen, hot mammary glands usually indicate mastitis, a high-urgency infection requiring immediate veterinary care to prevent life-threatening sepsis. Seek emergency treatment if the skin changes color or your cat becomes lethargic.
What causes swollen and painful mammary glands in my cat?
Swollen, hot, and painful mammary glands in cats are most often a sign of mastitis, an infection of the breast tissue. This condition is common in nursing mothers but can occasionally occur in non-pregnant cats. Other possibilities include feline mammary hypertrophy (rapid benign growth) or mammary tumors, though heat and sudden swelling typically point toward an inflammatory or infectious process.
Is mastitis in cats considered a veterinary emergency?
- Urgency Level: High. This condition should be treated as an emergency because it can quickly lead to life-threatening sepsis.
- Seek immediate veterinary care if the glands are turning purple or black.
- Watch for systemic signs like lethargy and a refusal to eat, which indicate the infection is spreading to the bloodstream.
How can providing a photo help a veterinarian triage my cat?
- Allows the professional to assess the severity of inflammation and look for signs of tissue necrosis.
- Helps identify any abnormal discharge that may indicate a need for surgical intervention.
- Determines if the immediate priority is stabilization with IV fluids and antibiotics or emergency surgery.
Clinical Context (Merck Veterinary Manual)
In acute mastitis in cats, the affected mammary glands are hot and painful. If acute mastitis progresses to septic mastitis, systemic signs of illness such as fever, depression, anorexia, and lethargy may be seen, and the queen may neglect her neonates. Microscopic examination of milk may reveal inflammatory cells; milk from each gland should be evaluated in any postpartum queen with signs of systemic illness. Before beginning therapy, a milk sample should be collected (or obtained by fine-needle aspiration) for bacterial culture and sensitivity. Culture of fluid expressed from the affected glands often yields moderate to heavy growth of *Escherichia coli* or staphylococci. Hot-packing the affected gland encourages drainage and seems to relieve discomfort. Broad-spectrum, bactericidal antibiotics should be chosen based on sensitivity tests, understanding that they will be passed in the milk to the kittens. Cephalexin (5-15 mg/kg, PO, tid) and amoxicillin/clavulanate (14 mg/kg, PO, bid-tid) are recommended as initial therapeutic agents pending culture results. Tetracycline, chloramphenicol, or aminoglycosides should be avoided during lactation unless the neonates are weaned.
Chapter: Infectious Disease, Reproduction
Source: The Merck Veterinary Manual, 11th Edition (Page 1396)