Red flag symptoms
- Systemically unwell patient
- Night sweats
- Unintentional weight loss
- Chest pain
Anxiety is a common reason for sweating but more serious causes should not be missed. Excessive sweating, also known as hyperhidrosis, is a non-specific symptom and has a wide range of underlying causes.
Patients presenting with hyperhidrosis usually have associated symptoms which will indicate the likely cause, but it is important to enquire about the red flag symptoms listed in box 1 to exclude serious underlying pathology.
It is useful to note the duration and distribution of the sweating. An acute presentation may suggest infection or a cardiac cause. A chronic history would support a diagnosis of anxiety.
Although anxiety is a common cause of sweating, other causes must be considered first and it should be noted that night sweats would be unusual in cases of anxiety.
If the sweating is focal (in palms, soles or axillae) and has persisted for more than six months, consider a diagnosis of primary localised (focal) hyperhidrosis if at least two of the following features are present:
- bilateral and symmetrical sweating
- excessive sweating at least once a week
- disruption of daily activities
- cessation during sleep
- positive family history
The patient should be asked about recent travel and occupation as well as other risk factors for infection. A full drug and alcohol history should be taken.
A thorough physical examination should be undertaken, checking for lymphadenopathy, hepatomegaly and splenomegaly. Pulse and blood pressure should be recorded. Thyrotoxicosis and phaeochromocytoma can cause tachycardia and atrial fibrillation. The patient’s temperature should be taken if there is any concern about infection.
First-line blood tests would include a full blood count and inflammatory markers to check for infection and malignancy and a thyroid function test to rule out thyrotoxicosis.
Hypoglycaemia can be a cause of sweating, so a finger prick blood glucose test (preferably at the time of sweating) may be useful. If the patient is acutely unwell, blood glucose should be checked.
If menopause is being considered, ask about other symptoms and consider follicle-stimulating hormone testing in women under 45. An electrocardiogram should be performed if indicated by examination findings and a chest x-ray requested if infection, especially tuberculosis, or malignancy is suspected.
Phaeochromocytoma is a rare diagnosis but if under consideration, 24-hour urinary catecholamines can be done. It is important to ensure the urine collection is performed according to local laboratory protocols, as the result may otherwise be misleading. If the index of suspicion is high, a referral to an endocrinologist for investigation would be appropriate.
Possible causes of hyperhidrosis
- Drugs - alcohol, drug withdrawal, venlafaxine
- Infection - HIV, tuberculosis, infective endocarditis
- Acute coronary syndrome
- Primary localised hyperhidrosis
People should be advised to avoid any obvious triggers. Simple self-care options include using antiperspirants, avoiding tight clothing, changing clothes more regularly and wearing white or black clothing to minimise signs of sweating.
People can also try alternatives to occlusive footwear and having alternate pairs of shoes to allow them to dry out. 20% aluminium chloride preparations can be helpful for symptom relief and they should be applied correctly as per their instructions.
Any anxiety around the symptom should be managed accordingly. There are some useful information leaflets provided by the British Association of Dermatologists, NHS and International Hyperhidrosis Society that patients can be signposted towards.
Beyond these measures, referral to a dermatologist should be advised for consideration of further treatments.
Key learning points
- Red flag symptoms in hyperhidrosis include a systemically unwell patient, night sweats, unintentional weight loss and palpitations or chest pain
- Focal, persistent sweating that disrupts daily life may indicate primary localised hyperhidrosis
- Consider anxiety, drugs, infection, malignancy, thyrotoxicosis, diabetes and phaeochromocytoma as causes
- Patients should avoid obvious triggers and take simple self-care measures
This module first appeared on GPonline on 5 February 2010. Original author: Dr Kamilla Porter. Updated by Dr Anish Kotecha, a GP in Gwent