There are a few common causes of an itchy bottom, and we may find no cause, in which case we call it pruritus ani. In children, threadworms are very common – but it's rare in adults. This is a parasite infection causing intense itching around the anus and possibly the vagina, especially at night. You might notice tiny white worms around your child’s anus or mixed in their poo. In adults, haemorrhoids may be to blame. You may be able to feel one lump or more on the anus, and it may be painful when you go for a poo. You may get a few streaks of blood in the toilet bowl or on toilet tissue. These are common and treatments are available. Infections from a fungus or yeast (thrush) can feel itchy and sore. The area will look pink, perhaps with tiny pink bumps and possibly flaky. Psoriasis can look similar, but will likely be more red rather than pink and with a clear border, and is a more likely cause if you have psoriasis on other parts of the body. Eczema may appear around the bottom, especially if you have a tendency to it or if you have an irritation from any cream or treatments you are using, such as perfumed moisturisers, steroid creams or ointments for anal fissure. Genital warts can appear as hard lumps around the anus and wider genital area and may be itchy to start with. These are sexually transmitted and contagious to intimate partners. Finally, a condition called lichen sclerosus causes the skin to tighten, and this can be itchy. You might see some white streaks on the affected area and it might look shiny and taut.
Threadworms are very contagious, passing from bottom to hands or clothes to mouth, so it's important to get prompt treatment and re-treat 2 weeks later. Follow simple hygiene: wash hands and nails regularly, keep fingernails short and rinse the toothbrush before use. Children should wear underwear at night and wash it in the morning, and bed linen, towels, nightclothes and soft toys should be washed on a high cycle after treatment. Fungal infections can be contagious to other areas of your body, such as the rest of the genitals or other areas of skin. If you have a fungal nail infection, it would be worth getting this treated as this can transfer to areas of skin (and vice versa). Any non-infectious causes would not be contagious.
You should try to avoid itching and keep fingernails short - avoid tights, synthetic materials or other underwear than can cause sweating, and make sure you pat the area dry after bathing. Products from your pharmacy can be used to help soothe and cool the area (such as aloe vera gel or menthol creams, or ointments or creams containing bismuth subgallate or zinc oxide), emollients (medical grade moisturisers), and a mild steroid cream can calm any inflammation. If you think you or your child has threadworms, products containing mebendazole 100mg such as Ovex chewable tablets or liquid are available at the pharmacy, and are licensed for use in adults and children over 2 years in combination with simple hygiene measures. A single dose is taken by all members of the family aged over 2 years. A second dose to avoid re-infection should be taken after two weeks. It’s not recommended for pregnant or breast feeding women, or those under 6 months. You will need a prescription for any children aged 6 months to 2 years.
If you think your child has threadworms, you can buy a remedy from your pharmacist to resolve it. Similarly, you can try over-the-counter treatment for thrush or a fungal infection (they are treated with the same cream) and for haemorrhoids. If you are unsure of the diagnosis or you think this is lichen sclerosus, you should book a routine appointment with your doctor. If the itch is very severe or it’s painful, book an urgent appointment. You doctor will ask about symptoms and examine the area. They may be able to prescribe something to resolve it or ease symptoms. If your doctor can’t see anything to indicate why you have an itch, they may consider extra tests such as a swab or blood tests. It’s worth bearing in mind that a slight itch can evolve to become intense and all-consuming, and this can develop into an itch-scratch-itch cycle that is difficult to break. See your doctor if your itch is persistent or you notice any skin changes around the area.
Children do not need to stay off school with threadworms.