Norwegian Scabies – What Are They?
Scabies is a skin disease caused by the mite Schistosomum herpetestium (Herps). Scabies is a very common skin infection which affects nearly all mammals. The mites live in warm moist environments such as under beds, furniture, clothing and other human contact items. When they come into direct contact with humans, they bite their hosts causing the itching and burning sensation.
The mites have four stages of life: egg, larva, nymph and adult. They are transferred from host to host through direct contact, for example, through bedding or clothing. The scabies mites are very tiny and can only be detected with the use of a magnifying glass.
There are four types of Scabies, and seven different symptoms that can be caused by them, including intense itching and rashes. All types of Scabies cause a general redness and rash in the area where the mites are burrowing.
The most common type of scabies is called Norwegian Scabies or Crusted Scabies. It is caused by an immune system which is severely compromised. This type of scabies is common in people living in extreme poverty or those who are terminally ill.
What Are Norwegian Scabies?
The Norwegian Scabies, also known as crusted scabies, is a serious and highly contagious skin condition caused by a tiny parasite called Sarcoptes scabiei. These mites burrow into our skin and lay eggs, which causes intense itching and skin irritation. Norwegian scabies are more dangerous than other forms of scabies because they can cause severe skin problems. This may lead to the skin becoming thick and leathery or even riddled with open sores. These are the signs of Norwegian scabies.
Most people with normal immune systems can get rid of scabies within two weeks of treatment with lotion containing 5% Permethrin. However, people with weakened immune systems may experience a relapse of scabies in the future. People with this condition should use a lotion with 10% Permethrin instead.
Classification Of Norwegian Scabies
Norwegian scabies is classified into two sub-types: crusted and non-crusted. Crusted is the more severe form of Norwegian scabies. It is also called retiform scabies.
The non-crusted Norwegian scabies is also known as classical scabies. It occurs at any age and in all races and both sexes. The symptoms of Norwegian scabies are similar in both sexes and all age groups.
The crusted scabies appears only in people over sixty years of age. It is seen more commonly in men than in women.
Norwegian scabies usually causes very itchy skin. In many cases, people with Norwegian scabies also have a weakened immune system due to other skin conditions, diabetes or old age.
The non-crusted scabies is the most common form of this disease. It mainly occurs in children under 5 years old and in young adults.
The crusted Norwegian scabies accounts for 10 to 20% of all cases of scabies. It occurs more commonly in elderly people or those who have a weakened immune system.
The difference between the scabies mite which causes Norwegian and other types of scabies is that it has a long life cycle. The adult mite lives for about a month. In healthy people, it takes about 3 to 5 weeks for the mites to mature and lay eggs.
The adult mites mate and lay eggs, which hatch in 3 to 4 weeks. The hatched mites then mature — a process that takes 2 to 3 weeks.
In humans, Norwegian scabies lives in the skin layer. It lives and lays eggs in the epidermis or just below it. The entire life cycle takes around 2 to 5 weeks.
Causes Of Norwegian Scabies
The cause of scabies is a tiny parasite called Sarcoptes scabiei or the scabies mite. It burrows itself in our skin to lay eggs. The eggs of these mites cause severe itching and a rash due to an allergic reaction.
The female mites burrow into the top layer or epidermis of our skin to lay eggs. These mites are so small that they can only be seen through a microscope.
The scabies mite is not known to cause any illness in humans or animals. While the disease called scabies only affects humans, you can get rid of scabies mites by using special medication.
A female mite can live for about a month or until it lays eggs. After mating, she will lay about 5 to 7 eggs in her lifetime. The eggs take 3 to 4 weeks to hatch.
The newly hatched mites are very tiny and cannot burrow into the skin right away. They grow and mature into adults in 2 to 3 weeks. These adult mites can live up to 3 to 4 weeks.
Practicing good personal hygiene and reducing the scabies mite’s surroundings will help prevent a new outbreak of scabies.
Risk Factors For Norwegian Scabies
If you have had scabies once before, you are more likely to develop the disease again. This is known as a reinfestation of scabies.
If you live in a community where many people have scabies, you are also at greater risk of getting reinfested.
Children in daycare centers are at high risk of getting scabies. This is why it is very important to check for scabies in these facilities.
If you have close contact with someone who has scabies or has been reinfested, you also have a high risk of developing the disease.
Signs And Symptoms Of Norwegian Scabies
Most people with scabies do not develop any physical signs. The only way to find out if you have scabies is to see your doctor for a diagnosis.
Sources & references used in this article:
- New insights into disease pathogenesis in crusted (Norwegian) scabies: the skin immune response in crusted scabies (SF Walton, D Beroukas… – British Journal of …, 2008 – Wiley Online Library)
- Crusted (Norwegian) scabies in patients with AIDS: the range of clinical presentations. (I Schlesinger, DM Oelrich, SK Tyring – Southern medical journal, 1994 – ncbi.nlm.nih.gov)
- Crusted (Norwegian) scabies. (KA Kolar, RP Rapini – American family physician, 1991 – europepmc.org)
- Crusted (” Norwegian”) scabies in a specialist HIV unit: successful use of ivermectin and failure to prevent nosocomial transmission. (EL Corbett, I Crossley, J Holton, N Levell… – Sexually Transmitted …, 1996 – sti.bmj.com)
- Crusted scabies: alias Norwegian scabies (LC PARISH, C LOMHOLT – International Journal of Dermatology, 1976 – academia.edu)
- Ivermectin for crusted (Norwegian) scabies (F Aubin, P Humbert – New England Journal of Medicine, 1995 – Mass Medical Soc)
- Crusted scabies looking like psoriasis (JE Gach, A Heagerty – The Lancet, 2000 – thelancet.com)