What could cause swelling on the right side of the lower abdomen?

There are a number of potential explanations for swelling in the right lower abdomen:

• Complications from appendicitis: A perforated appendix can lead to an abdominal wall abscess or even fistula formation. This creates a localized swelling that could be painful and associated with signs of infection.
• Appendiceal Mucocele: This unusual condition occurs when the appendix becomes distended due to the accumulation of mucus. In some instances, this mass may be mistaken for a right adnexal (ovarian) mass, but it originates from the appendix.
• Abdominal Wall Endometriosis: In women, endometrial tissue can sometimes implant in the abdominal wall. When this happens on the right side near the lower abdomen, it can form a painful, localized mass that may fluctuate with the menstrual cycle.
• Mesenteric Lymphadenopathy: Enlarged mesenteric lymph nodes, often visible on imaging, can result from infections, inflammatory conditions, or even be part of a systemic process. These clusters of nodes can present as a palpable swelling.
• Ovarian cysts with or without rupture. These may present as pain to one side of the abdomen, and in the case of ovarian torsion, it would be a medical emergency.
• Rare Conditions: Although less common, disorders such as neuronal intestinal dysplasia—a developmental condition affecting the intestines—might also present as an abdominal mass.

Because these causes differ greatly in severity and management, it is important to seek evaluation from a healthcare provider. You can start by taking a free AI symptom checker assessment to help identify potential causes based on your specific symptoms, then discuss the results with your doctor. They can carry out a physical examination, recommend appropriate imaging studies, and perform further diagnostic tests to determine the exact cause of the swelling and to guide necessary treatment.