Scabies has been know throughout history as "the itch," and it's this feature --intense itching-- that is most often the first, and most prevalent symptom of scabies. Usually the itch is most concentrated on the hands, especially in the webbing and back, and sides of the fingers, as well as the skin folds of the wrist; however, many different parts of the body may be affected. Usually the first sign of scabies that you can see are small pink or red dots or bumps that look like hives, tiny bites, or pimples. Be cautious however, this is only the typical or 'classical' way that scabies appears; scabies may appear in many different forms.
Visual symptoms of scabies: what do they look like, and where are they found?
Scabies on the head – Most articles you'll read will state that scabies don't show up on the head, except in children or in people with immune system disorders. This isn't true! Scabies do live on the head!
In tropical countries, scabies are found on the head. I assume that this is due to the high moisture content of the air, which increases the range of sites on the body that scabies can survive on.
The fact that scabies can live on the head in tropical climates, and my assumption that it's due to humidity, leads me to ask if they are able to survive on the head in non-tropical but moist climates, such as where I live, in the Pacific Northwest. My answer is yes they do ihabit the head - I've felt them on my ears. So treating the head might be worth considering... I treat my ears.
- Scabies can be on almost any part of the body, but often the hands are the first area affected. Scabies also particularly like to live in skin folds and crevices, such as those on the inside of the wrist.
- An early scabies rash will usually be a few small red dots – like hives or tiny bites or pimples. These dots may start out as a light shade and darken with time.
- In dryer, cooler climates, a short, (0.5-1 cm) thin, wavy line, that's grayish and slightly raised, can be seen. These have been described as looking like narrow pencil marks. These are called burrows. These burrows often appear in the webbing of the fingers. These burrows can be made easier to see using a felt pen.
- Other areas that are often affected are the inside of the forearm, insides of the elbows, shoulder blades, underarms, nipples, breasts of women, belly (especially the navel), buttocks, penis, inner thighs, ankles and the feet (particularly in tropical countries).
- In children, scabies often shows up under the arms as red dots.
- The head and face typically are not affected as often in non-tropical climates, except in children or those with weakened immune systems.
Unusual or non-typical signs of scabies
No visual signs of scabies - I've experienced this
myself, and talked with quite a few people who also
haven't had any signs of scabies except itching. This
is disturbing, because it can lead one to doubt that they
have scabies at all - or to doubt their sanity.
In people with immune disorders, and in the elderly, the body may react differently to scabies, leading to an intense infestation know as Crusted, or Norwegian scabies.
Scabies may show up as nodules; these are little (2-5 mm) brownish-red raised bumps, usually 1-15 in number. Nodular scabies tend to appear more often in children.
Sometimes, though rarely, there may not be any visual sign of scabies. This usually occurs if somebody is taking steroids or antihistamines that mask the signs of scabies, or in people who have had scabies previously; however, a lack of visual signs may also occur in without any apparent reason.
What do they feel like?
The feel of the itching may vary: scabies can itch in a superficial way, sort of like a flea bite or a mosquito bite, or sometimes there will be a more intense "pin prick wriggling" sensation under the skin. Also, large areas of the body, such as the upper back or inner arm, can tingle or "crawl." The most usual spot for itching is between the first and second knuckles on the back of the fingers and in between the fingers, but itching may occur anywhere. Itching tends to become worse at night, during exercise, and hot baths.
Note: People who are taking drugs that suppress the immune system may not feel scabies.
Scabies really does look different on different individuals. I imagine that its presentation is usually a combination of how an individual's particular immune system reacts, climate, and grooming habits, and possibly (though I haven't read about this), slight variations of the mite - sarcoptes scabiei var. hominis.
If an individual reports an intense itch, has visual signs of scabies, then a diagnosis of scabies usually assumed and no tests are made. The diagnosis is strengthened if somebody else the individual has had close contact with is itchy or been diagnosed with scabies, Often, during an outbreak, a doctor will see many cases of scabies, making the diagnosis of new cases more easier and more certain.
Problems diagnosing scabies
Scabies are notoriously difficult to diagnose, for this reason, it's a good idea to make sure your doctor has a lot of experience diagnosing scabies, or to ask for a referral to a dermatologist. Here some of the reasons why scabies can be difficult to diagnose:
- A negative scraping test for scabies is inconclusive; in other words, even if the scraping test fails to find any scabies, they may still be present.
- Though scabies may have a typical set of symptoms, these can, by no means, be relied on. Scabies may look and feel very different in different individuals, and can also look different in different climates.
- Many rashes and skin conditions can be mistaken for scabies (even by doctors!).
- The classical signs of scabies may be altered or destroyed by scratching leading to difficulty in diagnosis.
- Rashes associated with scabies can persist from a week up to a month after a successful treatment, leading to concerns over misdiagnoses, treatment failure, and over treatment.
if you get scabies for the first time, it's unlikely you'll know that you have it for four to six weeks. Within this time - when you don't have sign or symptoms of scabies - you can give scabies to other people. After you've had scabies once, your body becomes sensitized, and you usually know when you've gotten it again within a couple of days.
What are scabies?
The length of scabies life cycle can vary; it's my impression it can vary quite substantially.
The condition known as scabies is caused by a parasitic mite sarcoptes scabiei. The mite is an arthropod, related to ticks and spiders. It's quite unusual to see a mite unaided; the female, larger than the male, measures only about 0.4 mm in length, and are wider than they are tall - sort of turtle shaped. The mite burrows into the outer layer of the skin (stratum corneum) and feeds on skin cells and fluids. It's this feeding action, and it's products, (digestive secretions and feces) that provoke an immune reaction from the body which results in itching and the other symptoms of scabies.
The life cycle, from egg fertilization to reproductive maturity, occurs in about 10 days for males and 14 days for females. Females typically live for 30 days or more after reaching sexual maturity.
Mating, burrowing, and laying eggs
Male mites traverse their host's skin, seeking females' burrows; they are attracted to the openings of female mites' burrows, which contains large quantities of feces. The male enters the burrow of the female and mates with her. After mating, the female may seek a new burrow to lay her eggs, or expand her current burrow to accommodate her eggs. The adult female lives for about a month, and in that time she can lay 40 - 50 eggs.
In 3-4 days, the eggs hatch and a six legged larvae emerges (adults have six legs). The larvae remain in the female's burrow for up to one day, and then leave the burrow to excavate a burrow of their own.
Larvae grow and change form by shedding their exoskeleton (molting) three times before they reach adulthood (larva, protonymph, tritonymph, adult). Each molting takes 2-3 days, and each molting requires the excavation of new burrow (also called a molting pouch). After the final molt, the mite has reached reproductive maturity.