I quickly asked my mother to put the child on the treatment bed, opened her clothes and saw many small pustules on her hands. Just as I was wondering, I took a closer look and found a red papule on her left wrist with a thin line with cutin of about 0.3 cm. The diagnosis immediately appeared: scabies.
Mom couldn't believe it at all. She asked several times: Are you sure, doctor? None of us have symptoms. Are you really sure? So, I had to scrape off a piece of dander and examine it under a microscope. Sure enough, as I expected, two scabies mites and five eggs appeared under the camera, and my mother collapsed. ....
What do you know about scabies?
Scabies can be said to be one of the most terrible diseases in dermatology, not because of its severity, but because of its infectivity. I am afraid that people around me will be infected as soon as they get it, but is it really that terrible? How to face scabies is the focus of this paper.
Before getting down to business, let's think about a few questions. If you all know the answer, you can skip this article, but if you have any questions, please continue reading.
1. Can human scabies be transmitted by animals?
2. Can the sarcophagus jump or fly?
3. Sarcoptes can survive without human body? Or how long can you live?
4. How many scabies do scabies patients have on average? 10, 50, 100, 1000?
As long as you come into contact with scabies patients (such as shaking hands and hugging), you may be infected?
Human Sarcoptes vs Specific Parasitism of Animal Sarcoptes?
The scabies infected by humans are caused by the variety of scabies mites. Hominis
Animal scabies mites are parasitic on pigs, dogs, cats and other mammals, commonly known as animal scabies (including pig scabies, dog scabies, cat scabies ...).
When people come into contact with these animals suffering from scabies, these animal scabies mites can be transmitted to people. However, because these animal sarcoptes scabies are not suitable for parasitizing on human skin, the symptoms caused are mild and the parasitic time is short. There is no way to reproduce on human skin. It is self-limited and will not be transmitted to others and will not cause epidemics. There is no need to worry too much. As long as they stop touching these animals, they will heal themselves without treatment.
Similarly, human scabies can also be transmitted to these animals, causing similar symptoms, which is also temporary.
These different kinds of scabies mites are specific to their hosts.
Sarcoptes scabies is an obligate human parasite, which only infects people and does not parasitize animals.
The life span of sarcoptes scabies is about 1~2 months, and the whole life history is on human skin.
The sarcophagus itself does not have the ability to fly and bounce, but can only crawl. It can crawl on the skin at a speed of 2.5 cm per minute, but it can only drill about 0.5~5 mm per day in the wormhole.
Sarcoptes usually only live for a short time after leaving the host and are not very active. At room temperature (about 265438 0℃, relative humidity: 40~80%), they can't survive for more than 48 hours without a host.
Life history of sarcophagus-on human skin
Female insects lay 2~3 eggs in the wormhole every day. Eggs hatch into larvae (lava, only 3 pairs of feet) in 3~4 days, climb to the skin surface, then transform into larvae (if they are nymphs, they have 4 pairs of feet) in 3~4 days, and then transform into adults in 4~7 days.
At this point, the male and female insects mate and the male insect dies after mating. Females only need to mate once and are fertile throughout their life cycle. After fertilization, the female will start to move on the skin, find a suitable place, drill into the stratum corneum, form a wormhole, eat keratin for a living, lay eggs here and spend the rest of her life (about 1~2 months). Meanwhile, in the meantime, she will
Therefore, the whole life history is on human skin.
Leave the human body = a dead end! Survival time changes with the environment!
Basically, scabies don't like to leave the human body, because once they leave the human body, they can't survive for a long time.
At normal room temperature (265438 0℃, relative humidity: 40~80%), the survival time of sarcophagus is less than 48 hours.
If the ambient temperature rises to 34℃, it can only survive for less than 24 hours.
The temperature is above 50℃ (dryer) for no more than 10 minute. ?
On the contrary, if the ambient temperature is low and the humidity is high, the survival time will be prolonged.
(Reference: J Am Acad Dermatol. 1984 Aug； 1 1(2pt 1):2 10-5。 )
So if dehumidifiers can be used in places that are easy to happen, such as nursing homes, prisons, shelters and so on. At the same time, it can increase the indoor temperature and reduce the probability of the spread of scabies.
Therefore, the incidence of scabies in winter will be higher, and the environmental temperature is also part of the reason. But if the temperature is lower than 16℃, the activity of the sarcophagus will be greatly reduced and there is no way to enter the skin.
As can be seen from the above, the longer the sarcophagus leaves the human body, the lower the infectivity.
How many scabies does a typical scabies patient have?
The skin of scabies patients is covered with scabies. Is it big ~ flat ~ flat ~ Actually, it's not like this. According to statistics, only about 65,438+00% eggs can finally hatch into adults under suitable conditions.
At the same time, we will remove bugs by scratching, and the immune response will also fight against the sarcophagus. Therefore, the number of human sarcophagus is less than we thought.
According to statistics, there were only 10~ 12 scabies in the first three months of infection.
How does scabies spread?
Generally speaking, scabies are spread by direct skin contact. Because scabies don't jump and climb slowly, the infectivity is related to the number of scabies in patients, the skin contact range, the length of time and the persistence.
The risk of infection will increase with the increase of the number of skin scabies, especially scabbed scabies patients, which are the most contagious. They have millions of scabies, and even falling dander is contagious. ?
In addition, indirect contact with articles used by patients may also be infected, but whether they can be infected by these pollutants is still controversial. Some scholars have pointed out that the sarcophagus can't grow without a host, and it can't jump or walk well. No host, only a dead end. So it's not easy to get infected here.
What is this? Direct skin contact infection? ? You can get infected by touching it?
As mentioned just now, scabies are spread through skin contact. As long as you have touched a scabies patient, will you get it? Every time I see a consultation, if the patient is diagnosed as scabies, the whole nursing station will be full of sadness, and the main nurse will generally feel itchy. I hope to see the doctor by the way to see if there is infection, and the whole nursing station will be mobilized.
Direct contact with the skin, as long as it comes into contact with the patient, it will not be contagious. Because the sarcophagus does not jump and crawls slowly, it takes at least 5~ 10 minutes for the sarcophagus to move from the patient to the contact (some documents think it takes 15~ 10 minutes).
Therefore, if you just shake hands, hug and touch the skin with typical scabies patients, you won't get it. ?
Even if these sarcoptes do run to the medical staff, the medical staff can actually wash their hands to kill sarcoptes immediately after examining the patient, because it takes 20 to 30 minutes for sarcoptes to drill into the stratum corneum, and then washing their hands can erase sarcoptes from the skin. ?
Hand decontamination can't kill the sarcophagus. ?
Usually, if you suspect that the patient has scabies, it will be safer to wear gloves for examination.
What is this? Indirect contact * * * infected by the article? ?
In theory, scabies can be spread through sheets, clothes and blankets, but in fact, typical scabies are quite rare, because once scabies leave the human body, their infectivity will drop rapidly. At the same time, the typical scabies patients only have 10~20 scabies, and then what?
A study showed that the bed sheets and clothes used by patients with severe scabies were only 3%(2/63) and 1.4%(4/272) respectively.
This infection mainly occurs in scabbed scabies. Because there are only 5~ 12 scabies in typical scabies patients, and there are millions scabbed scabies, even falling dander is contagious, so these patients are highly contagious, especially for medical staff.
People susceptible to scabies
According to statistics, about 300 million people worldwide are infected with scabies every year. The incidence of male and female students is the same. Generally, vagrants are more susceptible to infection than ordinary people, and the incidence of children is higher, especially children under two years old and some popular tropical countries.
In addition, if the crowd is too crowded, for example, in winter, we prefer to get together and are more susceptible to infection, as well as people with poor hygiene habits, malnourished people, people with mobility difficulties/bedridden people and people with decreased immunity.
The prone place of scabies
Because there are quite a number of rehabilitation wards in our hospital, which can be said to be the first in Central China, there are a lot of inpatients, many of whom are rehabilitation patients transferred from hospice care institutions or other hospitals. In the early days, as long as skin rashes appear before these patients move in, they will definitely inform dermatologists, hoping that they will not wait for a period of hospitalization to develop into existing scabies, which may be transmitted to other patients or rehabilitation technicians and nursing staff. Therefore, from the perspective of residents, after all, when the patient's family members want you to give an answer (once diagnosed, they must leave the hospital and can't do rehabilitation, which will cause great trouble), the nursing staff also hope that you can make a correct judgment (otherwise infection or nosocomial infection will be bad). How to make a correct diagnosis, you really have to try to find out the evidence of infection and avoid killing someone by mistake.
In addition, places where other people will live together for a long time, places where direct skin contact is easy, such as prisons, shelters, nursing homes, etc., are prone to occur.
When I leave prison, I always talk about eating pig's trotters and washing sulfur water. Actually, it's because there are often scabies in prison.
Then, let's take a look. Once scabies run to the body, will symptoms appear immediately? Does the skin have to have a rash? Does it have to itch? How to detect that you may be infected with scabies? (How to detect scabies by yourself? How to diagnose? )
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