• Determine whether the hyperhidrosis is primary focal (idiopathic), or secondary to an underlying cause:
• Suspect an underlying cause if any of the following affect the person with hyperhidrosis:
• Generalized sweating.
• Sweating during sleep (which suggests tuberculosis, another infection, or Hodgkin's disease).
• Symptoms and signs of systemic disease (such as fever, weight loss, anorexia, or palpitations).
• The person is taking prescribed drugs that are known to cause sweating.
• Unilateral or asymmetric sweating (which suggest a neurological lesion or tumour, an intrathoracic malignancy, or a cervical rib).
• Symptoms and signs of any other causes of secondary focal hyperhidrosis or generalized hyperhidrosis.
• Diagnose primary focal hyperhidrosis if diagnostic criteria are met.
• Assess whether anxiety may be an exacerbating factor.

• Causes of generalized hyperhidrosis include:
• Pregnancy.
• Anxiety.
• Prescribed drugs:
• Anticholinesterases (pyridostigmine, neostigmine).
• Antidepressants (venlafaxine, duloxetine, selective serotonin reuptake inhibitors, tricyclic antidepressants, trazodone, and mirtazapine).
• Pilocarpine (eye drops to treat glaucoma).
• Bethanechol (a bladder stimulant).
• Propanolol.
• Substance or alcohol abuse or withdrawal (see the CKS topic on Alcohol - problem drinking).
• Cardiovascular disorders: heart failure, myocardial ischaemia, shock (see the CKS topics on Heart failure - chronic and Angina).
• Respiratory failure.
• Infections, such as tuberculosis (see the CKS topic on Tuberculosis), and brucellosis (which can cause nocturnal sweating), HIV, abscess, and malaria.
• Malignancy: Hodgkin's disease, myeloproliferative disorders.
• Endocrine or metabolic disorders or conditions: thyrotoxicosis, hypoglycaemia, phaeochromocytoma, acromegaly, carcinoid tumour, hyperpituitarism, obesity, gout, menopause.
• See the CKS topics on Gout, Hyperthyroidism, Menopause, and Obesity.
• Neurological disorders and lesions: Parkinson's disease, diencephalic epilepsy, hypothalamic lesions.
• See the CKS topics on Parkinson's disease and Epilepsy.
• Familial dysautonomia (Riley–Day syndrome).
• Causes of secondary focal hyperhidrosis include:
• Neurological disorders, such as stroke (see the CKS topic on Stroke and TIA), peripheral neuropathies, diabetic autonomic neuropathy (see the CKS topic on Diabetes type 2) and other neuropathies, spinal cord lesions, and tumours (all which may directly cause hyperhidrosis, or indirectly result in compensatory hyperhidrosis).
• Intrathoracic neoplasms (e.g. mesothelioma — see the CKS topic on Lung cancer - suspected) or a cervical rib, both of which can cause unilateral hyperhidrosis.
• Gustatory sweating (sweating induced by food or drink) may be due to:
• Diabetic neuropathy (see the CKS topic on Diabetes type 2).
• Herpes zoster of the preauricular area.
• Invasion of the cervical sympathetic trunk by a tumour.
• Injury or surgery to the parotid gland such as that experienced in Frey's (auriculotemporal) syndrome.
• Cutaneous disorders: blue rubber-bleb nevus, other eccrine nevus or nevus sudoriferous, sudoriferous angioma, glomus tumour.
• Other: Raynaud's phenomenon, erythromelalgia, arteriovenous fistula, cold injury, rheumatoid arthritis, pachyonychia congenita, pachydermoperiostosis, nail-patella syndrome.
• See the CKS topics on Raynaud's phenomenon and Rheumatoid arthritis.

Determine whether hyperhidrosis is primary focal (idiopathic), or secondary to an underlying cause.

• This recommendation, and features suggestive of an underlying cause, are based on expert opinion from Guidelines for the primary care treatment and referral of focal hyperhidrosis [Lowe et al, 2003] and a US expert consensus statement [Hornberger et al, 2004].

Causes of secondary focal and generalized hyperhidrosis

• These are derived from the US consensus statement [Hornberger et al, 2004], two guidelines [Lowe et al, 2003; International Hyperhidrosis Society, 2008a], and review articles (including a review of causes of drug-induced hyperhidrosis) [Leung et al, 1999; DTB, 2005; Glaser et al, 2007; Cheshire and Fealey, 2008; Gee and Yamauchi, 2008; Solish et al, 2008].

Assess whether anxiety may be an exacerbating factor

• This recommendation is based on expert opinion that anxiety can aggravate primary focal hyperhidrosis, expressed in published review articles [Cheung and Solomon, 2002; Hornberger et al, 2004; Solish et al, 2008] and in comments from external reviewers.

• Diagnose primary focal hyperhidrosis when focal, visible, excessive sweating:
• Occurs in at least one of the following sites: axillae, palms, soles, or craniofacial region, and
• Has lasted at least 6 months, and
• Has no apparent cause, and
• Has at least two of the following characteristics:
• Bilateral and relatively symmetrical.
• Impairs daily activities.
• Frequency of at least one episode per week.
• Onset before 25 years of age.
• Positive family history.
• Cessation of local sweating during sleep.
• If symptoms have lasted less than 6 months or onset is at 25 years of age or older, primary focal hyperhidrosis remains a likely diagnosis if other criteria are met, but extra care should be taken to exclude an underlying cause.
• If the presentation is characteristic of primary focal hyperhidrosis and there is no evidence of an underlying cause, no laboratory tests are needed.

• The recommendations, including diagnostic criteria for primary focal hyperhidrosis, are based on expert opinion from a US expert consensus statement, Recognition, diagnosis, and treatment of primary hyperhidrosis [Hornberger et al, 2004]. The use of these diagnostic criteria is widely advocated [Glaser et al, 2007; Gee and Yamauchi, 2008; International Hyperhidrosis Society, 2008b; Solish et al, 2008].
• The statement, 'If symptoms have lasted less than 6 months or onset is at 25 years of age or older, primary focal hyperhidrosis remains a likely diagnosis if other criteria are met, but extra care should be taken to exclude an underlying cause' is the opinion of CKS.