🧭 When to suspect

Hyperhidrosis is sweating in excess of that needed for thermoregulation, arising from overactive eccrine sweat glands. It is common: primary focal disease affects roughly 1% of the population, and although benign, the impact on work, relationships and mood is frequently profound.

First separate primary from secondary hyperhidrosis, and never miss a sinister cause.

Suspect primary focal hyperhidrosis when there is visible, excessive, focal sweating lasting at least 6 months with no apparent cause, plus at least two of:

• Bilateral and relatively symmetrical.

• Onset before age 25.

• Frequency of at least one episode per week.

• Impairment of daily activities.

• A positive family history.

• Cessation during sleep.

Primary focal hyperhidrosis typically affects the axillae, palms, soles or craniofacial region.

Severity is graded with the Hyperhidrosis Disease Severity Scale (HDSS), a patient-rated 1–4 score in which 3 or 4 denotes severe disease and drives escalation.

Feature	Primary (focal)	Secondary
Distribution	Focal, bilateral & symmetrical (axillae, palms, soles, craniofacial)	• Often generalised • May be unilateral or asymmetrical
Onset	Childhood or adolescence, usually before 25	• Any age • Often new in adulthood
During sleep	Stops during sleep	May persist or wake the patient (night sweats)
Family history	Positive in 30–50%	Usually absent
Other clues	• Otherwise well • No systemic features	Weight loss, fever, palpitations, lymphadenopathy, or a drug cause

🧠 Clinical pearl

• Whether the sweating stops in sleep is the most useful bedside discriminator.

• Primary focal hyperhidrosis switches off overnight.

• Drenching sweats that soak the sheets and wake the patient are a different problem and mandate a search for lymphoma, tuberculosis or chronic infection before anything is labelled "primary".

Source: British Association of Dermatologists · British Journal of General Practice

🔒 Sign up free to read the full topic

You're viewing a free preview. Create a free account to unlock the rest.

Inside the full topic 🔒 History🔒 Red Flags🔒 Examination🔒 Patient Explanation🔒 Investigations🔒 Management🔒 Non-pharmacological Treatment🔒 Pharmacological Treatment🔒 Special Notes🔒 Referral Pathways🔒 Take Home Messages

Sample topics are open to everyone in the Free Sample Bundle.

Part of The Ocean Library, 450+ structured clinical topics mapped to the primary care curriculum. Companion audio in Echo · one-page summary in The Scope.