Hyperhidrosis, i.e. inappropriate high-volume sweating, occurs in various disorders.

Hyperhidrosis in cancer:
The prevalence of hyperhidrosis in advanced malignancy may be as high as 14-28%.
Sweating is particularly associated with
• Hodgkin's disease and several other types of malignant disease
• Widely disseminated malignancy
• Liver metastases
• Infection
• Paraneoplastic conditions
• Hormonal insufficiency
• Drugs
• Withdrawal syndrome seen after the abrupt discontinuation of various psycho-active drugs, including opioids.
Sometimes there is more than one cause, e.g. both liver metastases and morphine.

Pattern: in malignant disease, it may occur only at night ('night sweats'), and tends to be paroxysmal. If there is associated pyrexia, there is no fixed pattern. Thus it may be continuous, intermittent, remittent, low-grade, hectic, or any combination of these types.
Evaluation: Although there are several objective tests to determine the pattern and extent of hyperhidrosis, these are generally inappropriate in patients with advanced cancer. As with other symptoms, the diagnosis of the cause of the sweating is based largely on probability and pattern recognition. Paraneoplastic sweating is a diagnosis of exclusion. Consider checking the white blood cell count and examining the urine for pus cells. Urine and blood cultures and a chest radiograph are sometimes also appropriate. At some centres, 'blind' antibiotic therapy is used as a diagnostic test.

Management:
Correct the correctibles:
• treat infection with the appropriate antibiotic
• hormone deficiency after castration: hormonal or non-hormonal treatment
• if a TCA (tricyclic antidepressant) or an SSRI(Selective Serotonin Reuptake Inhibitor) is the cause, switch to venlafaxine
• if morphine is the cause, consider switching to an alternative strong opioid

Non drug therapy:
• reduce ambient temperature
• encourage air-flow, e.g. draught, fan
• diet: avoid very hot drinks, spicy food
• less bed-covers
• avoid plastic covers on pillows and mattress

Symptomatic drug therapy:
• Begin by prescribing an antipyretic: paracetamol 500-1000 mg p.r.n.
• NSAIDS: naproxen, diclofenac or indomethacin
• If the sweating does not respond to an NSAID, prescribe an antimuscarinic drug: propantheline, thioridazine, amitriptyline
• If an antimuscarinic fails, other options include: propranolol, cimetidine, olanzapine
• Thalidomide should be the last resort even though the response rate appears to be high because of the likelihood of an irreversible painful peripheral neuropathy

Twycross R. Sweating in advanced cancer. Indian J Palliat Care 2004;10:1-11. Internet. Accessed on July 16, 2016.