LCH provokes a non-specific inflammatory response, which includes fever, lethargy, and weight loss. Organ involvement can also cause more specific symptoms. Bone: The most-frequently seen symptom in both unifocal and multifocal disease is painful bone swelling. The skull is most frequently affected, followed by the long bones of the upper extremities and flat bones. Infiltration in hands and feet is unusual. Osteolytic lesions can lead to pathological fractures. Skin: Commonly seen are a rash which varies from scaly erythematous lesions to red papules pronounced in interiginous areas. Up to 80% of LCH patients have extensive eruptions on the scalp. Bone marrow: Pancytopenia with superadded infection usually implies a poor prognosis. Anemia can be due to a number of factors and does not necessarily imply bone marrow infiltration. Lymph node: Enlargement of the liver in 20%, spleen in 30% and lymph nodes in 50% of histiocytosis cases. Endocrine glands: Hypothalamic pituitary axis commonly involved. Diabetes insipidus is most common. Anterior pituitary hormone deficiency is usually permanent. Lungs: Some patients are asymptomatic, diagnosed incidentally because of lung nodules on radiographs; others suffer from chronic cough and shoness of breath. Less frequently gastrointestinal tract and central nervous system. Ref: Kliegman, Behrman, Jenson, Stanton (2008), Chapter 507, "Histiocytosis Syndrome of Childhood", In the book, "NELSON TEXTBOOK OF PEDIATRICS", Volume 2, 18th Edition, New Delhi, Page 2159