Patients with hairy cell leukemia often have a very indolent disease and may not be diagnosed after several months or even years of illness. The symptoms may be divided into those related to the effects on their bone marrow, effects due to organ involvement, and secondary complications due to infections or those due to autoimmunity.

Bone Marrow Disease

Low red blood cell count or anemia can develop slowly but go as low as hemoglobin of 3-4 grams /dl with normal usually of 14-16 grams /dl. This can result in marked fatigue and weakness, shortness of breath, and or dizziness.

Low white blood cell count especially low neutrophils which are important in fighting infection and patients can present with recurrent infections including pneumonias.

Low platelet count to life-threatening levels where severe spontaneous bleeding can occur and patients may notice increased nosebleeds or gum bleeding, increased bruising, and even have severe bleeding from their stomach.

Organ Involvement

Patients may have the hairy cells go from bone marrow to other organs. Most prominent include the spleen. A common finding in up to 90% of patients is an enlarged spleen even two to three times normal. This can cause pain on the left side where the spleen is located, early feeling of fullness in the stomach thus difficulty eating, and in some cases death of spleen tissue or infarct with severe pain and or spleen rupture.

The liver may also be involved leading to pain in the right side and abnormalities of the liver activity leading to leakage of fluid in the abdomen called ascites.
Although uncommon, hairy cells can invade the bones and cause bone destruction with severe bony pain.

Lymph nodes may be affected and enlargement can cause pain whether in nodes in the neck or the abdomen.

Finally there can be involvement in the brain causing headaches or abnormalities of brain function.

Secondary Complications

Patients with hairy cell leukemia can have a disturbed immune system due to changes in their blood cells, not just the neutrophil, but also other cells important in protecting against infection. Unusual infections due to fungus and viruses can affect the skin, lungs liver, and brain. Symptoms from these can include that of pneumonia with fever cough and sob. Patients may develop a painful rash due to reactivation of chicken pox in their nerve called herpes zoster. If there is involvement of the brain patients may have severe headaches or confusion.

Autoimmune disease may be seen in up to 35% of patients in some published reports and usually present as inflammation of vessels called vasculitis and or joints and other tissues. Patients may have increased joint pain and swelling, unusual skin rashes, or systemic symptoms of fever and weight loss. This can occur as a presenting sign or any time during the illness.


Patients with hairy cell leukemia may develop many different symptoms due to their illness and patients and doctors should be aware of the many associated problems that can occur. A careful history of the patient’s complaints may help localize the cause and allow for proper treatment.