When it is not just due to hot summer nights.

The symptoms of night sweats are a common outpatient complaint, but there are no data regarding its true actual frequency. For many, night sweats can be highly disruptive of sleep, especially when woken up in the middle of the night with your hair soaked, sheets drenched, and sweat pouring off you. Though it may be a simple side effect of hormonal changes associated with menopause for women of the right age group, but in some instances, it may also indicate a more sinister cause.

When does the occurrence of night sweats signal a real threat to your health? One should schedule a visit to your doctor if the night sweats occur persistently on a regular basis, or if it interrupts your sleep, and especially if it is accompanied by fever or other symptoms, such as  unexplained weight loss.

There are a number of causes of night sweats, although lymphoma and tuberculosis are the two main diseases in which night sweats are a dominant symptom. However, it may also be triggered by other causes including human immunodeficiency virus infections, some fungal infections, certain cancers, problems related to your body’s hormone-producing glands (endocrine system) and some classes of medications (Table 1).

TABLE 1. Causes of Night sweats


lymphoma, leukemia


Tuberculosis (TB), human immunodeficiencyvirus (HIV), infectious mononucleosis, fungal infections (histoplasmosis, coccidioidomycosis),brucellosis


menopause, pregnancy,hyperthyroidism, endocrine tumours (phaechromocytoma, carcinoid tumor)


antipyretics, antihypertensives, aspirin, anti-depressants, hypoglycemia agents


gastroesophageal reflux disease,obstructive sleep apnea, chronic alcohol abuse

Given the long list of causes for night sweats, it is important for us as physicians to listen to what our patients tell us and narrow down the possibilities. What doctors do is as much an art as it is a science.

“I can’t believe I have lymphoma. All this time, I thought my night sweats were just due to the warm summer nights from the effect of global warming.”

It was a Tuesday morning when Junita walked into my consultation room, nervous and tense after a long wait. Noticing her nervousness, I patiently waited for her to relax and listened to her entire story.

Her story began six months before the 23-year-old had seen multiple general practitioners for her complaints of generalized itch, and night sweats. She initially did not think much of her symptoms, but decided to see her family doctor when it persisted. She was initially told that it may be due to eczema or dry skin and was given topical lotions to apply. When her problems persisted, she sought medical attention with another doctor, who then told her she may be having “food” allergies and was prescribed anti-histamines medications. The medications did provide temporary relief but after a few weeks, her symptoms returned. Over the course of the next few months, she saw four other different doctors who prescribed her with more anti-histamines and topical creams but to no avail.

Junita was eventually referred to an infectious disease specialist, who conducted an extensive investigation to exclude an infectious etiology. By then, Junita had lost 5 kg or about ten percent of her normal body weight and she was also experiencing intermittent episodes of body chills  and fever. At that time, all the blood tests for an infectious etiology were negative. Finally, a computed tomography (CT) scan of the chest and abdomen was carried out. The radiologist found a large anterior mediastinal mass and some enlarged nodes around the intestines. These findings were suggestive of lymphoma, and were subsequently referred to me for further management. A needle biopsy of the mass confirmed the diagnosis of Hodgkin lymphoma.

Lymphoma is a cancer that develops from lymphocytes, a type of white blood cell found in lymphoid organs such as the lymph nodes, bone marrow, tonsils and spleen. It is, simply put, a cancer of the immune system. These lymphomas  may arise from either B lymphocytes or T lymphocytes. There are over 60 different types of lymphoma, and what my patient Junita had was just one subtype of lymphoma. However, all lymphomas share some similar features and the backbone of treatment is chemotherapy. We do not not know the cause of lymphoma for the majority of patients. But there are some known associations such as radiation exposure, occupation hazards from heavy chemical exposure, chronic infections like Epstein-barr virus (EBV) or human immunodeficiency virus (HIV), and environmental factors such as pollution and pesticide exposure may play a role in the development of lymphomas.

A standard work-up for lymphoma will include performing blood tests such as the tumor marker lactate dehydrogenase enzyme (LDH), a bone marrow biopsy and a lymph node biopsy or biopsy of any affected sites. A full body scan such a PET or CT scan is often done prior to treatment and is useful in determining the extent of disease. Lymphoma is still considered one of the cancers that are highly treatable and a good proportion of patients can even be cured from their cancers. Just like my patient, Junita, she is now five years in complete remission and is now a proud mother of two beautiful daughters.

After all these years, I still remember her words “Dr Tay, I can’t believe I have lymphoma. All this time, I thought my night sweats were just due to the warm summer nights from the effect of global warming.” In Junita’s case, thankfully this trust has been earned in her case. I truly believe that as doctors, we need to practice good clinical medicine, always asking the “whys” rather than just treating the symptoms. My own advice to my patients is to pay special attention to a persistent symptom and not ignore it. Sometimes, even a problem as benign sounding as night sweat can turn out to be something more ominous.

Dr Kevin Tay
Dr Kevin Tay is a consultant medical oncologist with the Oncocare Cancer
Centre and also a visiting consultant at the National Cancer Centre Singapore. Dr Tay received his medical degree from the National University of Singapore, School of Medicine and did his post-graduate training in Internal Medicine at the University of Hawaii and his Medical Oncology fellowship at the National Cancer Institute (NCI), National Institute of Health (NIH) in USA. Dr Tay was also appointed Chief
Resident and Chief Fellow during both his residency and fellowship program respectively.  He currently holds American Board certifications for the practice of Internal Medicine and Medical Oncology. Dr Tay’s subspecialty interest is in women-related cancers such as breast cancers and gynaecological cancers, soft tissue and bone sarcomas and also hematological malignancies such as lymphoma, multiple myeloma and leukemia.  www.oncocare.sg