Guidelines for management of patients up to 18 years with Langerhans cell histiocytosis has been suggested. Treatment is guided by extent of disease. Solitary bone lesion may be amenable through excision or limited radiation, dosage of 5-10 Gys for children, 24-30 Gys for adults. However systemic diseases often require chemotherapy. Use of systemic steroid is common, singly or adjunct to chemotherapy. Local steroid cream is applied to skin lesions. Endocrine deficiency often require lifelong supplement e.g. desmopressin for diabetes insipidus which can be applied as nasal drop. Chemotherapeutic agents such as alkylating agents, antimetabolites, vinca alkaloids either singly or in combination can lead to complete remission in diffuse disease.

Treatment with chemotherapy has been used with some success, particularly using lomustine, prednisone, doxorubicin, and cyclophosphamide. Because of the rapid progression of this aggressive disease, the prognosis is very poor.

Most histiocytomas will regress within two or three months. Surgical removal may be necessary if the tumor does not regress or if it is growing rapidly to a large size. Histiocytomas should never be treated with an intralesional injection of a corticosteroid, as remission relies on recognition of the tumour by the body's immune system which is suppressed by steroids.

Excellent for single-focus disease. With multi-focal disease 60% have a chronic course, 30% achieve remission and mortality is up to 10%.

Some patients have no symptoms, spontaneous remission, or a relapsing/remitting course, making it difficult to decide whether therapy is needed. In 2002, authors from Sapienza University of Rome stated on the basis of a comprehensive literature review that "clinical observation without treatment is advisable when possible."

Therapeutic options include surgery, radiation therapy, and chemotherapy. Surgery is used to remove single lymph nodes, central nervous system lesions, or localized cutaneous disease. In 2014, Dalia and colleagues wrote that for patients with extensive or systemic Rosai–Dorfman disease, "a standard of care has not been established" concerning radiotherapy and chemotherapy.

Current treatment options include:

- Surgical debulking

- High-dose Corticosteroid therapy

- Cyclosporin

- Interferon-α

- Chemotherapy

- Vemurafenib. It would appear that approximately half these patients harbor point mutations of the BRAF gene at codon 600 substituting the amino acid glutamine for valine. Vemurafenib, an oral FDA approved targeted agent to the BRAF protein for melanoma, shows dramatic activity in patients Erdheim–Chester disease whose tumor contains the same mutation. In 2017 the US FDA approved vemurafenib for this indication.

- Radiation therapy

All current treatments have had varying degrees of success.

The vinca alkaloids and anthracyclines have been used most commonly in ECD treatment.

The basis of management is to find and correct the underlying cause. Many times cats with EGC will respond to treatment with corticosteroids or to ciclosporin.

In secondary cases, treatment of the cause, where possible, is indicated. Additionally, treatment for HLH itself is usually required.

While optimal treatment of HLH is still being debated, current treatment regimes usually involve high dose corticosteroids, etoposide and cyclosporin. Intravenous immunoglobulin is also used. Methotrexate and vincristine have also been used. Other medications include cytokine targeted therapy.

An experimental treatment, an anti IFN-gamma monoclonal antibody tentatively named NI-0501, is in clinical trials for treating primary HLH. The FDA awarded breakthrough drug status to NI-0501 in 2016.

Treatment for X-linked SCID can be divided into two main groups, the prophylactic treatment (i.e. preventative) and curative treatment. The former attempts to manage the opportunistic infections common to SCID patients and the latter aims at reconstituting healthy T-lymphocyte function.

From the late 60s to early 70s, physicians began using "bubbles", which were plastic enclosures used to house newborns suspected to have SCIDS, immediately after birth. The bubble, a form of isolation, was a sterile environment which meant the infant would avoid infections caused by common and lethal pathogens. On the other hand, prophylactic treatments used today for X-linked SCID are similar to those used to treat other primary immunodeficiencies. There are three types of prophylactic treatments, namely, the use of medication, sterile environments, and intravenous immunoglobulin therapy (IVIG). First, antibiotics or antivirals are administered to control opportunistic infections, such as fluconazole for candidiasis, and acyclovir to prevent herpes virus infection. In addition, the patient can also undergo intravenous immunoglobulin (IVIG) supplementation. Here, a catheter is inserted into the vein and a fluid, containing antibodies normally made by B-cells, is injected into the patient's body. Antibodies, Y-shaped proteins created by plasma cells, recognize and neutralize any pathogens in the body. However, the IVIG is expensive, in terms of time and finance. Therefore, the aforementioned treatments only prevent the infections, and are by no means a cure for X-linked SCID.

Bone marrow transplantation (BMT) is a standard curative procedure and results in a full immune reconstitution, if the treatment is successful. Firstly, a bone marrow transplant requires a human leukocyte antigen (HLA) match between the donor and the recipient. The HLA is distinct from person to person, which means the immune system utilizes the HLA to distinguish self from foreign cells. Furthermore, a BMT can be allogenic or autologous, which means the donor and recipient of bone marrow can be two different people or the same person, respectively. The autologous BMT involves a full HLA match, whereas, the allogenic BMT involves a full or half (haploidentical) HLA match. Particularly, in the allogenic BMT the chances of graft-versus-host-disease occurring is high if the match of the donor and recipient is not close enough. In this case, the T-cells in the donor bone marrow attack the patient's body because the body is foreign to this graft. The depletion of T-cells in the donor tissue and a close HLA match will reduce the chances of graft-versus-host disease occurring. Moreover, patients who received an exact HLA match had normal functioning T-cells in fourteen days. However, those who received a haploidentical HLA match, their T-cells started to function after four months. In addition, the reason BMT is a permanent solution is because the bone marrow contains multipotent hematopoietic stem cells which become common lymphoid or common myeloid progenitors. In particular, the common lymphoid progenitor gives rise to the lymphocytes involved in the immune response (B-cell, T-cell, natural killer cell). Therefore, a BMT will result in a full immune reconstitution but there are aspects of BMT that need to be improved (i.e. GvHD).

Gene therapy is another treatment option which is available only for clinical trials. X-linked SCID is a monogenic disorder, the IL2RG gene is mutated, so gene therapy will replace this mutated gene with a normal one. This will result in a normal functioning gamma chain protein of the interleukin receptor. In order to transfer a functional gene into the target cell, viral or non-viral vectors can be employed. Viral vectors, such as the retrovirus, that incorporate the gene into the genome result in long-term effects. This, coupled with the bone marrow stem cells, has been successful in treating individuals with X-SCID. In one particular trial by Cavazzana-Calvo et al., ten children were treated with gene therapy at infancy for X-SCID. Nine of the ten were cured of X-SCID. However, about three years after treatment, two of the children developed T-cell leukemia due to insertion of the IL2RG gene near the LMO2 gene and thereby activating the LMO2 gene (a known oncogene). A third child developed leukemia within two years of that study being published, likely as a direct result of the therapy. This condition is known as insertional mutagenesis, where the random insertion of a gene interferes with the tumor suppressor gene or stimulates an oncogene. There is currently no approved gene therapy on the market, but there are many clinical trials into which X-SCID patients may enroll. Therefore, research in the field of gene therapy today and in the future is needed to avoid the occurrence of leukemia. In particular, research into the use of insulator and suicide genes is warranted as this may prevent cancer from developing. The insulator gene inhibits the activation of adjacent genes. On the other hand, the suicide gene is stimulated when a tumour begins to form, and this will result in the deactivation of the therapeutic gene. Moreover, the use of restriction enzymes such as the zinc-finger nuclease (ZFN) is being studied. The ZFN allows the researcher to choose the site of gene integration. Vector safety is important in the field of gene therapy, hence vectors that self-inactivate the promoter and enhancer (SIN) and adenoviruses that creates no immune response are prominent areas of research for vector biologists.

In terms of treatment the following are done to manage the IPEX syndrome in those affected individuals(corticosteroids are the first treatment that is used):

- TPN(nutritional purpose)

- Cyclosporin A and FK506

- Sirolimus(should FK506 prove non-effective)

- Granulocyte colony stimulating factor

- Bone marrow transplant

- Rituximab

X-linked SCID is a known pediatric emergency which primarily affects males. If the appropriate treatment such as intravenous immunoglobulin supplements, medications for treating infections or a bone marrow transplant is not administered, then the prognosis is poor. The patients with X-linked SCID usually die two years after they are born. For this reason, the diagnosis of X-linked SCID needs to be done early to prevent any pathogens from infecting the infant.

However, the patients have a higher chance of survival if the diagnosis of X-linked SCID is done as soon as the baby is born. This involves taking preventative measures to avoid any infections that can cause death. For example, David Vetter had a high chance of having X-linked SCID because his elder sibling had died due to SCID. This allowed the doctors to place David in the bubble and prevented infections. In addition, if X-linked SCID is known to affect a child, then live vaccines should not be administered and this can save the infants life. Vaccines, which are pathogens inserted into the body to create an immune response, can lead to death in infants with X-linked SCID. Moreover, with proper treatments, such as a bone marrow transplant, the prognosis is good. The bone marrow transplant has been successful in treating several patients and resulted in a full immune reconstitution and the patient can live a healthy life. The results of bone marrow transplant are most successful when the closest human leukocyte antigen match has been found. If a close match is not found, however, there is a chance of graft-versus-host-disease which means the donor bone marrow attacks the patient's body. Hence, a close match is required to prevent any complications.

The prognosis is guarded with an overall mortality of 50%. Poor prognostic factors included HLH associated with malignancy, with half the patients dying by 1.4 months compared to 22.8 months for non-tumour associated HLH patients.

Secondary HLH in some individuals may be self-limited because patients are able to fully recover after having received only supportive medical treatment (i.e., IV immunoglobulin only). However, long-term remission without the use of cytotoxic and immune-suppressive therapies is unlikely in the majority of adults with HLH and in those with involvement of the central nervous system (brain and/or spinal cord).

Malignant histiocytosis (also known as "Histiocytic medullary reticulosis") is a rare hereditary disease found in the Bernese Mountain Dog and humans, characterized by histiocytic infiltration of the lungs and lymph nodes. The liver, spleen, and central nervous system can also be affected. Histiocytes are a component of the immune system that proliferate abnormally in this disease. In addition to its importance in veterinary medicine, the condition is also important in human pathology.

Interdigitating dendritic cell sarcoma is a form of malignant histiocytosis affecting dendritic cells.

It can present in the spleen. It can also present in the duodenum.

X-type histiocytoses are a clinically well-defined group of cutaneous syndromes characterized by infiltrates of Langerhans cells, as opposed to Non-X histiocytosis in which the infiltrates contain monocytes/macrophages. Conditions included in this group are:

A histiocytoma in the dog is a benign tumor. It is an abnormal growth in the skin of histiocytes (histiocytosis), a cell that is part of the immune system. A similar disease in humans, Hashimoto-Pritzker disease, is also a Langerhans cell histiocytosis. Dog breeds that may be more at risk for this tumor include Bulldogs, American Pit Bull Terriers, American Staffordshire Terriers, Scottish Terriers, Greyhounds, Boxers, and Boston Terriers. They also rarely occur in goats and cattle.

In pathology, dermatopathic lymphadenopathy, also dermatopathic lymphadenitis, is lymph node pathology due to skin disease.

Langerhans cells are dendritic cells (antigen-presenting immune cells) of the skin and mucosa, and contain organelles called Birbeck granules. They are present in all layers of the epidermis and are most prominent in the stratum spinosum. They also occur in the papillary dermis, particularly around blood vessels, as well as in the mucosa of the mouth, foreskin, and vagina. They can be found in other tissues, such as lymph nodes, particularly in association with the condition Langerhans cell histiocytosis (LCH).

Hand–Schüller–Christian disease is associated with multifocal Langerhans cell histiocytosis.

It is associated with a triad of exophthalmos, lytic bone lesions (often in the skull), and diabetes insipidus (from pituitary stalk infiltration).

It is named for the US-American pediatrician Alfred Hand Jr, the Austrian neurologist and radiologist Arthur Schüller, and the US-American internist Henry Asbury Christian, who described it in 1893, 1915/16 and 1919

Langerhans cell sarcoma is a form of malignant histiocytosis. It should not be confused with Langerhans cell histiocytosis, which is cytologically benign. Langerhans cell sarcoma is known to transform into leukemia. It can present in the lung, but such cases are rare.

ECD patients, families, and caregivers are encouraged to join the NIH Rare Lung Diseases Consortium Contact Registry. This is a privacy protected site that provides up-to-date information for individuals interested in the latest scientific news, trials, and treatments related to rare lung diseases.

Rosai–Dorfman disease, originally known as sinus histiocytosis with massive lymphadenopathy, is a rare disorder of unknown cause that is characterized by abundant histiocytes in the lymph nodes or other locations throughout the body.

Letterer–Siwe disease is one of the four recognized clinical syndromes of Langerhans cell histiocytosis (LCH). It causes approximately 10% of LCH disease and is the most severe form. Prevalence is estimated at 1:500,000 and the disease almost exclusively occurs in children less than three years old. The name is derived from the names of Erich Letterer and Sture Siwe.

In medicine, histiocytosis refers to an excessive number of histiocytes, ("tissue macrophages"), and is typically used to refer to a group of rare diseases which share this as a characteristic. Occasionally and confusingly, the term "histiocytosis" is sometimes used to refer to individual diseases.

According to the Histiocytosis Association of America, 1 in 200,000 children in the United States are born with histiocytosis each year. HAA also states that most of the people diagnosed with histiocytosis are children under the age of 10, although the disease can afflict adults. The University of California, San Francisco, states that the disease usually occurs from birth to age 15.

Histiocytosis (and malignant histiocytosis) are both important in veterinary as well as human pathology.

Treatment for individuals with X-linked thrombocytopenia is typically focused on managing symptoms of the disorder. Splenectomy has been shown to improve platelet counts but also significantly increases the risk of life-threatening infections for patients with XLT. Therefore, these individuals must take antibiotics for the rest of their life to avoid fatal bacteremia. In the event of significant bleeding, platelet transfusions should be administered. Circumcision should be avoided for infant males with XLT due to the risk of bleeding and infection. Regular follow ups to track blood counts should be utilized as well as confirming that any medications, over the counter or prescription, will not interfere with platelet functioning.