Human scabies is caused by an infestation of the skin by the human itch mite (Sarcoptes scabiei var. hominis). The microscopic scabies mite burrows into the upper layer of the skin where it lives and lays its eggs. The most common symptoms of scabies are intense itching and a pimple-like skin rash. The scabies mite usually is spread by direct, prolonged, skin-to-skin contact with a person who has scabies.
Scabies can spread rapidly under crowded conditions where close body contact is frequent Scabies. Institutions such as nursing homes, extended-care facilities, and prisons are often sites of scabies outbreaks.
The adult female scabies mites burrow into the upper layer of the skin (epidermis) where they live and deposit their eggs. The microscopic scabies mite almost always is passed by direct, prolonged, skin-to-skin contact with a person who already is infested. An infested person can spread scabies even if he or she has no symptoms. Humans are the source of infestation; animals do not spread human scabies.
- In adults can be sexually acquired
- From infested person to household members
CRUSTED (NORWEGIAN) SCABIES
Some immuno compromised, elderly, disabled, or debilitated persons are at risk for a severe form of scabies called crusted, or Norwegian, scabies. Persons with crusted scabies have thick crusts of skin that contain large numbers of scabies mites and eggs.
The mites in crusted scabies are not more virulent than in non-crusted scabies; however, they are much more numerous (up to 2 million per patient). Because they are infested with such large numbers of mites, persons with crusted scabies are very contagious to other persons.
Persons with crusted scabies can transmit scabies indirectly by shedding mites that contaminate items such as their clothing, bedding, and furniture. Persons with crusted scabies should receive quick and aggressive medical treatment for their infestation to prevent outbreaks of scabies.
Symptoms usually appear 2-6 weeks after infestation. If a person has been infested before it can appear in 1-4 days.
The most common symptoms of scabies, itching and a skin rash, are caused by sensitization (a type of “allergic” reaction) to the proteins and feces of the parasite.
Severe itching (pruritus), especially at night, is the earliest and most common symptom of scabies.
A pimple-like (papular) itchy (pruritic) “scabies rash” is also common. Itching and rash may affect much of the body or be limited to common sites such as:
- Between the fingers
- Shoulder blades
Tiny burrows sometimes are seen on the skin; these are caused by the female scabies mite tunneling just beneath the surface of the skin. These burrows appear as tiny raised and crooked (serpiginous) grayish-white or skin-colored lines on the skin surface.
- Mostly a clinical diagnosis
- Whenever possible, the diagnosis of scabies should be confirmed by identifying the mite or mite eggs or fecal matter (scybala). This can be done by carefully removing the mite from the end of its burrow using the tip of a needle or by obtaining a skin scraping to examine under a microscope for mites, eggs, or mite fecal matter (scybala).
- Avoid skin to skin contact with any of the family members
- Bedding, clothing, and towels used by infested persons or their household, sexual, and close contacts (as defined above) anytime during the three days before treatment should be decontaminated by washing in hot water and drying in a hot dryer.
- Topical Permethrin all over the body excluding head and face or Oral Ivermectin
- For pruritus oral antihistamine may be used
- For crusted scabies: warm watr soaks followed by application of keratolytic agent(5% salicylic acid) plus oral ivermectin or topical permethrin
FOLLOW UP ADVISED AT 2 WEEKS
- If you know somebody with scabies try not to touch their skin
- Do not share clothes with the infested person
- Wash bedding and everyday clothes with hot water and dry at high temperature
- If you are not able to wash seal it in a plastic bug for upto 72 hours which will kill the bug.
IN A NUTSHELL
Reference: CDC, NEENAS DERMATOLOGY