Scabies is a term used to describe a parasitic skin infestation by a mite which burrows into the skin to lay its eggs, and causes severe pruritus (itch). New insects hatch from the eggs and can be spread to other parts of the skin by scratching and depositing scrapings from under the nails. After the mite enters the skin the persons’ body reacts by causing red itchy bumps or blisters to form.
The name ‘Scabies’ comes from the latin sarcoptes scabiei which is the mites’ official name. The mite is very tiny, 0.2 mm to 0.4 mm long, and cannot easily be seen without magnification. Contamination occurs fairly easily with direct contact.
Scabies is diagnosed by differentially noting particular symptoms such as incredibly itchy and red bumps, pimple-like nodules or blisters, small, clear, fluid-filled spots or lesions that are usually linear (i.e. in lines – that is the most important differentiating factor).
The mite burrows under the skin and so lines of visible burrows or grey-looking tunnels (around 1 cm long) on the skin surface between the fingers, along the forearms and elbows, the wrist, chest and neck, and in skin creases such as armpits and ano-genital areas, are commonly seen when using a magnified device.
Often the rash is difficult to see clearly because the mites bury into the skin, and so often the only indication is the itch and subsequent linear scabs. Elderly people may experience a more widespread rash due to loss of integrity of their skin and a higher histamine response, and children may experience infections in other areas, such as the face, scalp, palms and soles of the feet due to their softer skin in those areas.
Scabies is common right around the world and can therefore affect anyone at all. Having Scabies does not necessarily indicate poor hygiene. The lesions are always itchy but are often more so at night when the skin is very warm, or if the person is being reinfected by bed linen. They will normally be itchier after a hot shower or bath as well. Hot water and common insecticides designed for larger insects normally do not provide any major assistance and in fact may actually increase the itch or cause additional rashes unrelated to the Scabies rash.
Do I really have Scabies?
The itch associated with Scabies is referred to as Pruritus. Pruritus can occur for a number of reasons and may in fact indicate other issues that need to be assessed and dealt with. For instance, Pruritus is also associated with renal disease, endocrine disorders, hepatic disorders, dehydration, psychological disorders, HIV infection, Pediculosis (Lice) infection and fungal infections such as Pityriasis as well as some other skin diseases like Psoriasis and Eczema etc.
Additionally, often there are co-morbidity factors at play where there may be co-existing skin conditions and because there are two or more conditions activated at the same time, the overall symptoms may be a little confusing, resulting in an incorrect diagnosis or assessment by even some very knowledgeable professionals.
Therefore it is always best to see a professional such as a GP for initial assessment and treatment, but if that treatment fails to clear up the infection within 2-3 weeks, then a professional who specialises in skin conditions should be contacted as soon as possible.
Initial diagnosis involves noting the multitude of signs and symptoms or identifying the burrows on the top of the skin using magnification. Your GP can confirm Scabies by taking a skin scraping and then the lab can identify the mites and eggs under a microscope.
How did I get it?
Scabies is caused by having direct and especially prolonged contact with someone who is infected. Therefore, it may be picked up during sexual intercourse, by wearing a garment that is infected, from bed linen, lounges etc, although this is less common, or simply by travelling on packed public transport where you may have been in direct contact, for long periods, with someone who is infected.
Although pets do not normally cause human scabies infections, they can use a pet as a temporary host and transfer to humans. However, mites that are specific to pets do not infest humans as they don’t breed on humans and so there is no ongoing infestations. The mites can survive for up to a day and a half away from the host in normal circumstances, but maybe longer in any perpetually heated environment, such as on a pet.
How long does it take to treat?
Even if the Scabies have been effectively treated, the itch may persist for two to three weeks after treatment. Firstly, this may be due to the environment taking some time to be effectively treated and therefore the person may become reinfected several times during that period, but primarily the reason for it taking so long to eradicate the itch is because it is caused by the body’s immune system responding to the mites and may take some effort for the immune system to settle down.
You can talk to your health professional about treatments available to help with the itch during the treatment period, but If symptoms persist for longer than three weeks, you should see your doctor or other health professional for a review as there may be something else going on. If the pimples or spots become infected, antibiotics may be necessary.
Symptoms usually develop as long as two to four weeks after the initial infection. However, as the persons’ body remembers previous infections, if you have had Scabies before you will usually have a shorter incubation period and the symptoms appear within as short a time as 1 – 2 days, because the immune system takes less time to respond.
You may be infectious to other people even before the itch begins. Additionally, you may continue to be infectious to other people, and yourself, until all mites and eggs are eradicated.
Providing you do actually have Scabies, and not something else that has been misdiagnosed, and it is treated effectively using creams, lotions etc as well as successfully treating the environment (clothing, bedding, lounges etc), generally, a person is no longer infectious 24 hours after treatment. However, as reinfection is possible, a follow-up treatment in 7 days’ time is always a good idea.
Treatment for Scabies
Treatment involves applying creams or lotions specifically produced for treating scabies. Some good practices include:
- Shower and towel dry and then apply the cream or lotion.
- Use the cream or lotion sparingly but cover your whole body except eyes, nose and mouth, and especially ensure that the cream or lotion gets into all the areas between your fingers, under your nails, the soles of your feet and buttocks. You may need assistance from someone else to apply the cream or lotion to your back or use a soft pad with a long handle.
- Don’t wash your hands for 12 hours if possible and leave the cream or lotion on your body for at least 12 hours. Then wash thoroughly and reapply. Normally it is best to apply the cream or lotion at night, just after dinner, and after a shower, and then re-apply in the morning.
- If you wash your hands during that 12 hours then reapply the cream or lotion to your hands or any areas that have sweated.
- You may need to reapply the cream or lotion in 7 days time by the same double-application process as stated above in order to kill any recently hatched mites.
- Your sexual partners and all members of your family or household should also be treated with the scabies cream or lotion.
- Hot-wash, tumble-dry, or dry clean any clothes, bedding or towels used in the last 3 days before treatment to kill the mites.
- Mattresses and upholstered furniture can be vacuumed or gently ironed.
- As skin disease caused by mites can easily be confused with other skin diseases, treatment should not be undertaken until the diagnosis has been confirmed by your health professional.
- In order to ensure successful treatment and even if no itching or other symptoms are present in other people, all people in the same household should be treated at the same time because by the time Scabies is diagnosed in one person, many other people may have already been infested.
- People with scabies should be excluded from childcare, preschool, school and work until 24 hours after treatment i.e. 2 days in total.
- If items are unable to be laundered, hot tumble dried, vacuumed, ironed or sprayed, place them in a sealed plastic bag and leave them for 3 days before hanging them up to air.
- Spray shoes, slippers, dressing gowns, blankets, lounges and carpets to assist in eradication. This will also help to eradicate any mites on your pet as well. DO NOT SPRAY PETS DIRECTLY. Use the spray in a small not easily seen area first to ensure colour-fastness and defend against staining.
- When treating babies or children under 2, pregnant women, people with sensitive skin or elderly people, additional care should be taken. Babies under 12 months of age need special treatment.
- People who already have other forms of skin disease may require additional assistance. You should seek advice if you have any concerns in this area.