Night sweats in adults
0Stop — call 999 now — any one is enough
- Sepsis or shock: fever or rigors with collapse, confusion, fast breathing, or cold, mottled or blue skin; haemodynamic or severe respiratory compromise → 999
- New neurological deficit or severe chest pain → 999
- While waiting: if septic or unstable, urgent hospital treatment; do not delay antibiotics for blood cultures.
1Triage — by the associated features
| Picture | Action |
|---|---|
| Unwell | Sepsis, fever when immunosuppressed, suspected endocarditis, TB with significant illness, severe alcohol withdrawal → Same-day hospital |
| Any one | Drenching sweats, documented fever, or unexplained weight loss >10% over 6 months → examine nodes and spleen; targeted tests. Nodes or spleen → block 2 |
| Stable | Prolonged low-grade fever → Urgent investigation, not admission |
| None | Afebrile, weight-stable, normal nodes, clear vasomotor or drug cause → primary care |
2Screen — one row is enough
- Unexplained lymphadenopathy (Hodgkin or non-Hodgkin) or splenomegaly (non-Hodgkin), weighing fever, sweats, breathlessness, itch, weight loss → consider Suspected cancer haematology (NG12)
- Pallor, fatigue, bruising, recurrent infection, hepatosplenomegaly → consider very urgent FBC within 48 h; film suggests acute leukaemia → Same-day haematology
- Possible active TB: cough, fever, weight loss or haemoptysis plus TB risk (travel, origin, contact, immunosuppression) → chest X-ray and Urgent TB service; 3 sputum samples (NG33)
- New murmur + persistent fever (endocarditis), esp. prosthetic valve, device, injecting drugs → Same-day hospital
- Immunocompromised (HIV, transplant, biologics, steroids): febrile or opportunistic infection → Same-day; otherwise Urgent specialist advice
- Haemoptysis at 40+, or chest X-ray suggesting lung cancer → Suspected cancer lung (NG12)
3Assess
☐ Temperature, pulse, BP, SpO₂, weight vs last recorded ☐ All node groups incl. supraclavicular and epitrochlear; spleen and liver ☐ Murmur, chest, thyroid, teeth, skin; breast or testes where relevant
If persistent or unexplained: FBC (film if abnormal), CRP/ESR; others by picture (renal, liver, TSH, HbA1c). HIV test where HIV is in the differential (NG60). Chest X-ray if respiratory symptoms, fever, weight loss or TB risk. Not: LDH as a lymphoma screen; FSH aged 45+ with typical symptoms; routine panels; CT without red flags in the young.
4Classify — only if the screen is negative
- Environmental — warm room, heavy bedding, bedtime alcohol. No tests.
- Menopause (45–55; POI under 40) — flushes, changing periods. Not if weight loss, fever, nodes, chest symptoms or abnormal results.
- Drugs and alcohol — SSRIs/SNRIs, opioids, steroids, tamoxifen, GnRH analogues, hypoglycaemics, nitrates, CCBs; withdrawal. Check timing.
- Endocrine — hyperthyroidism (TSH first); nocturnal hypoglycaemia on sulphonylurea or insulin; phaeochromocytoma (episodic hypertension, headache, palpitations → metanephrines).
- Sleep apnoea — 2+ of snoring, witnessed apnoeas, sleepiness, waking headache, choking; sweats not diagnostic.
- Uncertain — "idiopathic" only after a reassuring assessment, with safety-netting; re-examine if anything changes.
5Treat today — doses: NICE/SPC, BNF, local formulary
- Menopause: after risk discussion, offer HRT, the most effective (combined if uterus; oestrogen-only after hysterectomy); consider transdermal if VTE risk, incl. BMI >30. Or menopause CBT; fezolinetant if HRT unsuitable. No paroxetine or fluoxetine with tamoxifen.
- Drug cause: reduce or switch only where safe; never stop antidepressants abruptly. Venlafaxine also causes sweating. All: cool room, layers, less evening alcohol.
- Nocturnal hypoglycaemia: reduce sulphonylurea, review insulin. Alcohol dependence: no abrupt stop without a withdrawal plan.
6Refer routinely
- Endocrinology: suspected phaeochromocytoma; confirmed hyperthyroidism (NG145).
- Sleep clinic: suspected OSAHS (NG202); urgently if driving for work or safety-critical job; DVLA advice.
- Menopause specialist: complex risk, breast cancer, POI, HRT contraindicated. Postmenopausal bleeding at 55+ not due to HRT → Suspected cancer
7Never reassure by
- A normal FBC when nodes are persistent or suspicious.
- Age 45–55 when there is weight loss, fever, nodes or chest symptoms.
- A negative first work-up labelled "idiopathic" without a safety-net.
- Recalled weight: compare with the recorded weight.
- No fever today in a patient taking antipyretics.
- Repeated empirical antibiotics for a cough that could be TB.
8Safety-net — say it, then document it
999 “Call 999 if you collapse, become confused, are very short of breath, have cold or mottled skin, new weakness or severe chest pain.” Same day “Contact us today, or 111 out of hours, for a fever with feeling very unwell, coughing blood, new breathlessness, or unexplained bruising, bleeding or tiny spots.” Few days “Book within a few days for a new lump, weight loss, a fever or cough that won't settle, or sweats getting worse.”
Remote or OOH: convert to same-day face to face if fever with feeling unwell, breathlessness, haemoptysis, bruising or bleeding, or a new lump is reported, or observations cannot be obtained. Review: results (incl. HIV) at 1–2 weeks; symptoms at 4–6 weeks.