Langerhans Cell Histiocytosis (LCH) is a rare disorder which most often affects children under 2 years of age. The cause of LCH is still not clear and individual cases vary so much so it is a difficult disease to explain.

LCH shares many features with cancer, but it is controversial as to whether it is really a type of cancer or not.  The cells involved in the disease (histiocytes) are not thought to multiply uncontrollably like cancer. Rather, they appear to migrate to a site within the body in abnormally large numbers or wander outside their normal tissue compartment.

LCH is not infectious but it may develop after an infection or may be inherited in some families. LCH can come and go spontaneously and is only life threatening should organs such as the bone marrow, liver or lungs be severely affected.

Signs & Symptoms

• Often occurs in bones, commonly the skull or a limb, and produces a painful limp.

• May show up as a severe scalp rash, groin rash or as reddish-brown pinhead spots on the body.

• Chronic ear discharge or enlargement of liver/spleen causing abdominal swelling.

• If the disease affects the pituitary gland (20-30% of cases) it causes diabetes insipidus, a condition in which the kidneys are unable to conserve water, resulting in excessive thirst day and night and the need to urinate frequently and in large amounts.

• Generalised symptoms – loss of appetite, poor weight gain, anaemia and recurrent fevers.

• Prominent eyes – known as exophthalmos.

• If lungs are affected – increase in breathing rate, pain in the chest or breathlessness.

Diagnosis

The initial diagnosis is made by performing a biopsy of the tissue. It is next necessary to determine the extent of the disease using a number of tests including an x-ray of lungs and bones, blood tests including liver function tests, bone marrow biopsy, lung function tests and water balance tests which measure the concentration of urine after an overnight fast.

Treatment

Treatment for LCH is only required if there are symptoms such as pain, fever, poor weight gain or if important organs are affected.

• In some cases no treatment will be given because LCH is a disease which may disappear spontaneously. If the disease is confined to one organ/site then local treatment may be directed to that organ. If disease is generalised, whole body treatment will be given.

• Chemotherapy and steroids are used to treat LCH. Radiotherapy is rarely needed as most bony lesions will respond to surgery or steroids.

• For patients with diabetes, insipidus replacement water balance pituitary hormone (vasopressin) may be required – usually in the form of nose drops.

Prognosis

Disease limited to single organs is usually not life threatening and the main aim of treatment is to prevent damage to those organs.  Widespread disease involving multiple organs has a greater risk of causing severe illness and treatment is usually more aggressive and implemented for a longer course.

Generally speaking, the younger the child and the more organs involved, the more aggressive the disease and a greater intensity of treatment is required. The disease tends to run a more chronic course the older the child becomes.