Patient’s Guide to Scabies

What is Scabies?

Scabies is an infestation caused by itch mite, Sarcoptes scabei (Fig.1). The microscopic mite burrows into the upper layer of the skin, where it lives and lays its eggs.

Sarcoptes scabei                                                      Fig.1 Sarcoptes scabei, the tiny mite which causes scabies

What is Crusted (Norwegian) Scabies?

Crusted scabies is a severe form of scabies that can occur in persons who have a weak immune system, are old, disabled, or debilitated.

 Who can get Scabies?

  • Scabies is found worldwide and affects people of all races and social classes.
  • It occurs commonly under crowded conditions, where close body and skin contact is frequent.
  • Institutions such as nursing homes, child care facilities and prisons are often sites of scabies outbreaks.

 How soon do symptoms of scabies appear?

  • If a person is suffering from Scabies for the first time, symptoms may take as long as 4-6 weeks to begin. An infested person can spread scabies during this time, even when he/she does not show symptoms.
  • In a person who has had scabies before, symptoms usually appear much sooner (1-4 days) after exposure.

What are the signs and symptoms of scabies?

  • Characterized by itching, which is more intense at night.
  • Typical lesion is a burrow – a gray thread like serpentine line with a minute bump at the end (burrows can be very difficult to see).
  • Small bumps and blisters

 Which parts of the body can be involved?

It affects specific areas of the body as mentioned below since it prefers thin hairless skin (Figs 2,3):

  • Webs of the hands,
  • Elbows,
  • Inner aspect of the wrists,
  • Feet,
  • Inner forearms,
  • Genitalia,
  • Armpits,
  • Umbilical area,
  • Buttocks,
  • In infants, scalp, face, palms and soles are also involved.

Involvement of webs of hands                                                                         Fig.2 Involvement of webs of hands

scabies baby                                                                   Fig.3 Involvement of soles in infants

How do you get scabies?

  • Transmission of the mites involves close person-to-person contact of the skin-to-skin variety.
  • Sexual physical contact can also transmit the disease.
  • It also spreads indirectly by sharing articles such as clothing, towels, or bedding used by an infested person

What are the complications of scabies?

  • Scratching the rash can cause skin sores.
  • Sometimes these sores become infected by bacteria.
  • After healing, the rash can leave discoloration.

 How is scabies infestation diagnosed?

  • Diagnosis of a scabies infestation is usually based on the history of itching, which is more intense in the night, customary appearance and distribution of the rash and the presence of burrows.
  • Diagnosis of scabies can be confirmed by identifying the mite, mite eggs, or mite fecal matter and carefully removing a mite from the end of its burrow using the tip of a needle or by obtaining skin scraping.

What is the possible treatment?

Treatment is possible by drugs called scabicides (scabi, cide-lethal), scabicides can be local (which are to be applied on the skin) or oral Scabicides.

Local applications

  • Permethrin 5% – overnight single application is the treatment possible, of choice beyond 2 months of age.
  • Crotamiton 10 %- two applications daily for 14 days is useful in children.
  • Benzyl benzoate, 25% – three applications at 12 hourly intervals.
  • Gamma benzene hexacloride, 1% – single application, to be avoided in infants.

Oral medicines

  • Ivermectin – single oral dose of 200 µg / kg body weight in children older than 5 years.

 How can treatment be made effective?

Scabies is very easily treated, provided  all the instructions are followed meticulously.

  • All close contacts of the patient, even if do not have itching, should be given a treatment at the same time.
  • Firstly, the body is to be hydrated with a bath.
  • Scabicide should be applied all over the body neck down (including free edge of nails, genitals, soles of feet). In case of children less than 2 years, the cream or lotion is also applied to the head and neck.
  • The medicine should be left overnight.
  • Laundering of bed linen and clothes should be done after the treatment.

How sooner after treatment will you feel better?

  • Though in most cases, a single application/dose is enough for treatment, itching may persist for up to 2-4 weeks after, for which you may be prescribed oral drugs.
  • Retreatment with scabicide may be necessary if itching continues beyond 2-4 weeks after initial treatment or if new burrows or rash continue to appear.