C96.5: Multifocal and unisystemic Langerhans-cell histiocytosis

Multifocal and unisystemic Langerhans-cell histiocytosis (LCH) is a rare medical condition where the body produces an excess number of Langerhans cells, a type of cell that helps the body fight infections. These excess cells can build up in different parts of the body, leading to a variety of symptoms based on where they accumulate. In multifocal and unisystemic LCH, these cells pile up in multiple spots within a single system, such as the bones, skin, or lungs. Symptoms, therefore, correspond to the affected system. If bones are impacted, one may experience pain, fractures, or swelling. When the skin is involved, rashes or ulcers may appear. If the lungs are affected, difficulty breathing or persistent cough might be issues. The disease progression varies and it is not contagious. The exact cause is unknown.