What are scabies and Causes of scabies?

What are scabies and Causes of scabies

Scabies is a skin disease caused by a mite that can be spread easily. It is still a reasonably common disease anywhere in the world. Could you find out how it is treated?

It is called scabies, a skin disease caused by a mite ( Sarcoptes scabiei ) that can be spread easily. Although it is more challenging to find scabies today, it is still a fairly common disease in any part of the world. It affects all types of people regardless of gender or race. The usual thing is those small epidemics arise within the same family and in nursing homes or students since the mite is transmitted by direct contact with an infected person.

Scabies is a disease that knows no borders. In Europe, 1% of the population may suffer from scabies sometime in their life. In Latin America, scabies has a similar frequency, between 1-5%, but epidemic outbreaks occur more frequently, especially in Chile and Argentina. The percentage increases among older people, reaching up to 15% in some countries, especially if they suffer from other diseases at the same time. There are no differences between social strata; that is, both people with a low economic level and those who have a high economic level suffer from scabies with the same frequency.

In general, scabies is not an infection that puts people who suffer from it at risk. However, it does give many annoying symptoms, mainly due to itching. When properly diagnosed and treated, almost all cases are cured. It can only be a problem in people whose immune system is depressed, as in AIDS patients or those who have had an organ transplant.

Causes of scabies

The parasite that causes scabies in humans is called Sarcoptes scabiei. Scabies has traditionally been associated with poor hygiene, but today it is known that this is not the case. The mite is transmitted by skin-to-skin contact, either in daily living or in sexual contact; it can live up to three days outside the skin.

The mites pierce the most superficial layer of the skin, the so-called horny layer, which is made up of a substance called keratin, and once inside, they form tunnels that end in a broader point called “acarine eminence.” They live there, lay their eggs, and die. The larvae can escape to the outside through the tunnels and infect the same skin or other people.

Risk factors for scabies

The most important risk factors for contracting scabies are situations in which the probability of coming into contact with the mite increases. Some of them are:

  • Living with a person who suffers from scabies, in the day-to-day contact between family members or roommates is frequent.
  • Entering into occasional intimate contact with someone who suffers from scabies, especially in a sexual relationship, is not considered a sexually transmitted disease.
  • Although contagion is quite rare, sharing sheets or clothes is quite rare unless transferred immediately after an infected person has used it.
  • Living in camps, residences, prisons, military academies, etc.

Animals can also get scabies, but it is caused by another type of mite and cannot be transmitted to people. Neither is it a means of contagion to bathe in swimming pools, use public baths, or go to saunas.

Symptoms of scabies

The symptoms of scabies begin to appear between three and six weeks after infection. If it is the second time that an episode of scabies has been suffered, the symptoms will appear much earlier (in less than a week). The initial symptoms are:

  • Itching: it is the main and best-known symptom of scabies; when all family members start to itch at the same time, it is almost certainly due to scabies. At first, the mite does not cause itching, but when it begins to invade the skin, our body becomes sensitized, and days later, it defends itself with an allergic reaction. This mechanism has been studied about allergy to mites. At first, the itching is localized. It is only felt in the areas where the parasite is found, but later, the whole body itches. It increases at night or when it is hot since the mite is more active in high temperatures.
  • Primary lesions: these are the alterations caused by the parasite itself. The most common is to find fine grayish grooves in the skin (as if a pencil drew them) that end on a broader point. These are the manifestations of the tunnels and the acarine eminence that forms the mite. The parasite usually invades areas of the skin with little hair; the most frequent places are the forearms, wrists, and the skin between the hand’s fingers. In babies and young children, the skin is thinner, so the parasite can be found on palms, soles, and even on the scalp.
  • Secondary lesions: these are skin alterations that occur due to having scabies, but not directly by the parasite. The most important ones are:
  • Vesicles: are fluid-filled lumps that are formed by our body’s allergy to the parasite. They are tiny, like the tip of a pencil. The places where they appear most frequently are the buttocks, thighs, and around the navel.
  • Reddish nodules: they also appear as a result of an allergy, are larger (up to two centimeters in diameter), and have a reddish-brown color. They are found in the groin, armpits, and back. Sometimes they need to be removed with surgery because they last a long time after scabies have healed.
  • Lichenification of the skin: When a person constantly scratches to relieve the itch, the skin defends itself by becoming thicker and resembles lichen, hence the name. When there is no more scratching, the skin will return to its normal state.
  • Wounds: scratching the skin itself can cause minor skin wounds. By breaking this natural barrier, bacteria can take advantage of it to cause infections such as impetigo, cellulitis, folliculitis, and so on.
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