Lymphopenia is a common finding from a full blood count, especially in elderly patients, where it is usually of no clinical significance. No further investigation is advised in an elderly patient with a lymphocyte count >0.5×109/L in the absence of any concerning symptoms.
Symptomatic patients with persistent lymphopenia should be referred to the most appropriate specialty based on clinical and laboratory features.
Most cases are reversible and do not require specialist evaluation. The lymphopenia may reflect a response to stress such as acute infection or recent surgery or be iatrogenic secondary to medication, especially immunosuppressant drugs such as steroids
In those with unexplained moderate to severe lymphopenia (lymphocyte count <1×109/L) offer HIV testing
Persistent lymphopenia that remains stable over a six month period and in the absence of symptoms, clinical findings, or abnormal results from investigations does not require further investigation
Common causes in adults
- Infection – HIV, hepatitis, influenza, tuberculosis
- Medications – e.g. corticosteroids, methotrexate, azathioprine, rituximab
- Autoimmune disease such as rheumatoid arthritis and SLE
- Inflammatory bowel disease
- Renal failure
- Cardiac failure
- Malnutrition
- Alcohol use
- Surgery