A diagnosis of LCH is usually made following a biopsy and microscopic examination of the affected tissue. If the biopsy is positive for LCH, there are some other tests which will be conducted to determine the extent of disease so that a treatment plan can be made. Since LCH can be present in many areas of the body, physicians will usually order blood tests, x-rays, urine tests, and CT scans, along with performing a complete physical examination, to check all of the commonly affected body systems. Sometimes other biopsies will be done if test results or abnormal findings during the physical exam cause the physician to suspect involvement of another area.

Treatment of LCH depends upon the individual patient and the areas of involvement. As was mentioned before, some patients may have limited involvement, which does not progress or spread to other areas, while others experience widespread involvement affecting vital organs. Consequently, the treatment varies with the extent of disease. Some patients may need no treatment, while others benefit from limited surgery, small doses of radiation therapy, or chemotherapy. If it is determined that no treatment is necessary at the time of diagnosis, the physician will likely monitor the disease regularly to be sure that there is not further progression of the existing areas and that new areas of involvement can be detected and treated early. The ultimate goal of an overall treatment plan, of course, is to use as little treatment as possible to keep the disease under control to preserve quality of life and prevent the histiocytosis from damaging vital organs.