Suggest Treatment For Hyperpigmentation And Low Platelet Count

My baby was 5 days old when she was confined to the hospital. She has hyperpigmentation and low platelet count. The doctors considered TORCH infection. She was discharged after 13 days without a diagnosis since the TORCH assay result was negative. But we had a follow check up with the hematologist because her platelet count was 38 when she was discharged. After two weeks, her platelet count increased to 157 but her hemoglobin count dropped from 120 to 98 and the lymphocytes increased. The doctor performed bone marrow examination and found out that some cells are destroyed. Now they are considering histiocytosis. They want a skin biopsy and more tests to make a correct diagnosis. How can they diagnose my daughter s disease? Is this curable?Please help us. We can send pictures if needed.