👉 Platycnemia is a condition where the body's immune system becomes too active and attacks the lining of the stomach. This can lead to digestive problems, including bloating, gas, and cramping. In humans, it usually occurs in children under 2 years old because their immune systems are not fully developed yet. However, it can also happen in adults who have a weakened immune system or certain medications. Platycnemia is often caused by infections, such as bacterial or viral