Latching, hatching and scratching: All you need to know about scabies (but were definitely afraid to ask)

Explainer: Imagine a tiny mite using its front legs and mouth to carve its way under your skin. Now imagine hundreds of them doing it. Now imagine hundreds of them laying their babies in this little skin nest. Are you feeling itchy yet? News of increased scabies cases among student populations in Aotearoa is enough to make most people feel a bit scratchy. But how do you know if you've got scabies and what can you do about it if you do? Let's get under the skin of this issue.

What are scabies?

Sarcoptes scabiei var. hominis, otherwise known as scabies, are ectoparasitic mites that get their kicks from cavorting on human skin. They use their mouths and front legs to burrow into the outer layer of the skin, then lay their eggs there. These larvae hatch after three or four days and move to the skin's surface, where the cycle begins again. It's the circle of life, hakuna matata styles, only itchier.

What does it feel like when you have scabies?

Scabies are maddeningly itchy and - as anyone who has had them will tell you in acute detail - make you want to scrub at your skin with a wire brush. Greek philosopher Aristotle called them 'the lice of the flesh', which gives you a fair idea of what it's like to play host to these hungry critters. Scabies like to hang out all over the body, but they're most commonly found in skin folds (between fingers and toes, or in the armpits, elbow, belly button, groin area or around the waist). Having a scabies infestation often looks like a series of thin, wavy tunnels under the skin. And of course, the itch is a clear giveaway.

Why do they make you SO itchy?

The itch is an allergic reaction to the mites, their eggs and - there's no easy way to get past this - their poo.

That's revolting! Why then does scratching a scabies itch feel so good?

When your body reacts to a scabies party by itching, your skin sends receptors to the brain to tell it that something is going very wrong. When you respond by scratching, you temporarily damage these signals so your brain sends pain-relieving chemicals (including the happy hormone, serotonin) to the area.

However, this temporary joy is short-lived - and if you scratch too aggressively, you run the risk of tearing the skin and causing a secondary infection that's harder to treat and fix.

What's the treatment?

It's best to see a doctor to make sure that what you have is scabies. A special insecticide cream containing 5 percent permethrin generally does the trick. This cream is subsidised and available via prescription, though stocks are currently low nationwide.

Argh! How do you make the itch stop?

Good old-fashioned calamine lotion can be helpful here. There's also some evidence that tea tree oil can ease the itching when applied to the skin. It's important to remember that scabies - and their itch - won't go away unless you've had treatment.

How can I protect myself and my whanau?

Scabies need human skin contact to survive. If someone in your household or whanau has scabies, it's highly likely that the rest of you will get them too so the best course of action is for you all to be treated. In the meantime, avoid close (skin-to-skin) contact with the infected person. Bedding and clothes used or worn by the infected person should be washed and dried (or dry cleaned). If they can't be washed, store them in a closed plastic bag for up to a week.

What if you're scratching from head to foot and yet it doesn't seem to be scabies?

Don't ask us, we're journalists, not doctors. Make an appointment with your local medical centre if you've got concerns. And like your mum said, scratching will only make it worse!