The presence of a psoas abscess typically causes a certain amount of pain in patients. This is due to the swelling and inflammation caused by the infected material in the abscess, and may range from mild to severe. Many patients experience the pain in their lower back, side, or abdomen, though it may also radiate down into the groin and thigh.

Another common symptom of a psoas abscess is fever. These abscesses form due to a bacterial infection, typically caused by staphylococcus, which can be a direct primary infection of the muscle or a secondary infection that spreads from elsewhere in the body. As the body tries to fight off the infection, the patient may develop a fever along with the associated chills, body aches, and general feelings of malaise. They may also feel nauseous or lose their appetites, which can cause them to lose weight.

Frequent urination may also be the result of a psoas abscess. This is often the case particularly when the formation of the abscess is due to secondary infection from an existing infection in the kidney or bladder. Some patients, however, may not have any issues with urination, so it is important for a doctor to review all other symptoms during diagnosis.