Clinical tips: worms

toddler plays on grey shag rug

Brad Butt presents a guide to the OTC management of worms

Threadworms (aka pinworms) are the most common type of worm in humans. These long, thin worms draw their name from their thread-like appearance. They can grow up to 1.5cm long and tend to look like a small length of cotton thread.

Threadworms, like many worms, are parasites and live off their host, and most commonly their host are children under the age of 10. Because threadworms are highly contagious, good hand hygiene is paramount and as explained below it is the best way to limit their spread.

Contraction of worms can be directly from one person to another (eg via physical contact such as contact sport/holding hands) or indirectly (eg touching a door handle/furniture that an infected person has introduced the egg onto).

As you can see, this puts children into a higher risk group because they are in closer contact with each other and their hand hygiene habits are not engrained. It is important to remember that threadworms are a human-specific parasite and cannot be contracted from pets.

As far as diagnosis goes, its as simple as checking the stool after it has been passed. Threadworms would be visible as a short (1.5cm or less) threadlike piece of cotton.

The worms and possibly their eggs may also be visible around the anus of the patient while they sleep and may be seen with a torch and the naked eye; the eggs look like tiny white specks; these can often be identified by performing the stickytape test where you press a piece of sticky tape over the anus and remove—the eggs will stick to it and be visible as little white specks.

Other factors that may be suggestive of an infestation of worms include:

  • An itchy bottom
  • General irritability
  • Trouble sleeping, or restless sleep
  • Sudden lack of appetite

In some rare cases among girls, the female threadworms migrate from the anus to the vagina, which can lead to very uncomfortable vulvovaginitis. The symptoms of this include irritation and vaginal discharge. It will not survive for long in this region, but if you suspect vulvovaginitis, refer to the GP.

The other intestinal worms that humans are more prone to include hookworm, roundworm and whipworm—these tend to be far less common in Australia, however they will be investigated below.

Hookworm is considered relatively uncommon in Australia owing to the fact that it tends to be more prevalent in warmer climates where there is a higher population density and poor sanitation.

It is also an intestinal parasite but it tends to be contracted by people not wearing footwear outdoors where they come into contact with the larval worms.

These larval worms live in the soil as a result of contamination by dog faeces and tend to be more prevalent in northern Queensland (Ancylostoma caninum).

These larval worms penetrate through human skin and migrate through surface tissues causing inflammation. In most cases of human infection with dog hookworm this is as far as they go but in rare cases the immature worm is able to complete its journey through the body and reach the small intestine.

This parasite has been reported as the cause of a condition called eosinophilic enteritis (EE) in some people from north Queensland. It is characterised by inflammation of the small intestine (enteritis) causing abdominal pain with an associated increased level of white blood cells, called eosinophils, in the peripheral blood.

If a case of hookworm is suspected (noting symptoms are fairly nondescript), referral to the GP would be warranted. While products like pyrantel embonate can kill by paralysis it would still be advisable to see the input of the GP.

Roundworm, like hookworm, is considered relatively uncommon in Australia owing to the fact that it too is more prevalent in tropical and subtropical areas where sanitation and hygiene are poor. Roundworms also tend to be gastrointestinal worms, but certain species can travel to different areas of the body.

These worms tend to look a little like cooked spaghetti, and they range in size from just a few millimetres long, up to a meter or more.

Most people with roundworm infestation have few or no symptoms. Often the first symptom is live worms being passed in the stool or occasionally from the mouth, anus or nose.

In mild or moderate cases, the intestinal infestation can cause vague abdominal pain, nausea, vomiting, diarrhoea or bloody stools.

In heavy intestinal infestations, patients may experience severe abdominal pain, fatigue, vomiting, weight loss and a worm or worms in vomit or stool. Heavy infestation may aggravate nutritional deficiencies and impair growth in children or cause intestinal blockage by a bolus of worms.

Again, these worms can be managed with pyrantel embonate but it would be best managed by the GP.

Whipworm is considered rare in Australia owing to the fact that it too is more prevalent in tropical and subtropical areas where sanitation and hygiene are poor.

Whipworm infections are transmitted through the faeces of infected individuals, which contains eggs. The faeces which is passed can also end up being used as fertilizer, especially in some countries where sanitation is poor, and if these food items aren’t carefully washed, peeled and cooked, the eggs or larvae can end up being ingested, which kick-starts the infection cycle all over again.

Again, GP referral is recommended.

As you can now appreciate, the need for us, Australian pharmacists (and our patients), to manage worms other than threadworms is negligible. Anything other than threadworm is really best managed by the patients’ GP as symptoms at times hard to distinguish between.

Whilst some of these worms can be transmitted from our pets to us it is relatively unlikely that this is what will present at the community pharmacy.

In terms of management of worms, OTC items in Australia contain either mebendazole or pyrantel embonate. These preparations work by paralysing the worms; they are then passed out of the body with a bowel movement.

They will not however kill the unhatched eggs when taken which is why it is so important to retreat after 2-4 weeks if there are signs of reinfestation.

Pyrantel can be used from 1 year of age and dosed according to weight whereas mebendazole is only used in children over 2 and is a single dose of 100mg for all patients irrespective of age or weight.

So to recap!


  • Wash your hands before eating or preparing food, and after touching soil or using the toilet
  • Cut fingernails back and thoroughly clean under fingernails when treating for worms to reduce likelihood of reinfestination (hand to mouth infection)
  • When treating an infected individual, treat the entire family
  • Only drink bottled or boiled water in high-risk areas (places without modern toilets or sewage systems)
  • Deworm pet dogs and cats regularly (to minimise any risk of zoonotic disease)
  • Dispose of dog and cat poo in a bin as soon as possible (to minimise any risk of zoonotic disease)


  • Do not eat raw fruit and vegetables in high-risk areas
  • Do not walk barefoot in high-risk areas

Brad Butt is a passionate community pharmacist with a strong clinical background who takes pride in supporting the health of his patients and the wider community; special interests include men’s Health, childhood and maternal health, palliative care and the treatment and management of blood cancers.

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