Plantar hyperhidrosis
Also known as sweaty feet
What is plantar hyperhidrosis?
Plantar hyperhidrosis is a common condition affecting 1-3% of the population. The condition usually starts in childhood or adolescence. It can cause significant physical limitations and predispose to bacterial and fungal infections and friction blisters.
What causes plantar hyperhidrosis?
Many factors can contribute to plantar hyperhidrosis including genetic influences, as well as physical and emotional stress. A family history is present in up to 30% of cases.
What does plantar hyperhidrosis look like?
Plantar hyperhidrosis affects both feet equally. The condition can range from mild sweating through to severe constant sweating, but which stops when asleep.
What other problems can occur with palmar hyperhidrosis?
Plantar hyperhidrosis can occur on its own or in combination with other conditions. Severe cases can lead to infections such as tinea pedis, pitted keratolysis and other bacterial infections.
The condition can be very distressing due to its impact on quality of life.
Plantar hyperhidrosis can also be associated with increased sweating in other parts of the body including underarms (axillary hyperhidrosis), face and scalp (craniofacial hyperhidrosis).
How is plantar hyperhidrosis diagnosed?
Most cases are not associated with an underlying illness. The diagnosis is usually made based on a history of excessive sweating. No investigations are needed.
When there is evidence of tinea or bacterial infection a skin scraping and bacterial swab may be needed. Depending on the results, an anti-fungal or antibiotic cream or tablet may be recommended.
Further investigations are considered when excessive sweating affects larger areas of the body or if hyperhidrosis occurs during sleep.
How is plantar hyperhidrosis treated?
- General measures
The use of absorbent inner soles (summer soles) can help preserve your shoes. Double layered white cotton socks can help soak up excessive sweating. Changing socks frequently can help reduce the incidence of infections. The use of talc and powders can also help absorb excessive sweating. Shoe driers can help increase the lifespan of your shoes.
- Topical treatments
Mild cases of plantar hyperhidrosis can respond to topical treatments such as aluminium chloride hexahydrate (Driclor). Driclor should always be applied to skin that is as dry as possible in order to maximise the benefit and minimise potential side effects. Ideally, it should be applied just after a shower prior to bedtime. Dry the area off with a hairdryer on the cool setting then apply Driclor. Rinse your feet first thing in the morning with plain water (no soap). If irritation develops, applying a corticosteroid cream on alternate days can be useful (this needs to used be under the guidance of a health professional).
Anticholinergic creams such as glycopyrolate (0.5-3%) may be effective in managing plantar hyperhidrosis. A compounding pharmacist can make up these creams. The skin will absorb more cream if a foot scrub is used first.
- Iontophoresis
Iontophoresis may be considered for cases which do not respond to topical treatments. Treatments are individualised. The affected area is immersed in tap water, salty water or glycopyrrolate solution. Then a gentle electric current is passed across the skin surface for 10 to 20 minutes.
Glycopyrrolate iontophoresis has the highest success rate – up to 80% of affected people respond well to this treatment. The time between treatments will vary. Treatments will need to be repeated every 2 to14 days.
- Botulinum toxin type A (botox)
Botox injections can treat sweaty feet safely and effectively. However, the treatment is not subsidised under Medicare-PBS and the cost limits its wider use.
Botox treatment is usually performed under a nerve block. The amount of botox needed depends on the size of the feet. Usually 130 to 200 units of botox are needed in each foot.
The treatment is usually effective for 3 to 4 months.
Side effects include temporary muscle weakness.
- Oral medication
Anticholinergic tablets (such as oxybutynin and propantheline bromide) can be useful for plantar hyperhidrosos. However, side effects such as blurred vision, constipation, dry mouth and excessive drowsiness are common.
Other medications reported to be useful include oral glycopyrrolate (not available in Australia), propranolol, clonazepam and gabapentin.
Medication can be a viable short-term option for treating sweaty feet for several days to weeks and give people a “break” from their sweating.
- Surgery
Endoscopic thoracic sympathectomy is not a treatment option for plantar hyperhidrosis.
What is the likely outcome of plantar hyperhidrosis?
Plantar hyperhidrosis will often need ongoing and persistent treatment. However, some people may notice the amount of sweating decreases as they get older.
This information has been written by Dr Davin S. Lim