Scabies

Definition

Scabies is a contagious skin disease caused by mites called Sarcoptes scabiei which burrow into the skin surface thereby irritating the skin. The disease usually spreads from one person to another through close contact and therefore tends to thrive in crowded living conditions. The skin reaction is a result of the body’s immune system reacting to the presence of the mite. Scabies is a treatable disease and does not cause any permanent complications if managed properly.

Symptoms

  • Itching which can be severe and usually is worse at night.
  • Thin burrow tracks on skin with bumps or blistering, the burrows usually appear in the skin folds in between fingers, armpits, at the waistline, inner elbows and wrists, soles of feet, breasts, genital area, knees, buttocks.
  • The lesion may be associated with other skin conditions like eczema or dermatitis.
  • Vigorous scratching can lead to wounds and secondary infections usually by the group of bacteria that are normally present on the skin surface.

Crusted scabies (Norwegian scabies or hyperkeratotic scabies) is a severe form of scabies which presents as crusted lesions on the palms, soles or face.

Causes

Scabies is an infectious disease which is contagious. The mite burrows its way into the deeper layers of the skin and lays eggs which develop into larvae. The larvae come out of the burrows and take shelter in the creases of the skin where they can protect themselves from the environment and grow into adult mites. They live in warm areas and thrive on keratin, the protein substance of the skin.

The itching is caused by an allergic reaction against the mite and its eggs and waste products. The spread is usually through direct contact and rarely by using clothes or beddings of an infected person. The disease can spread rapidly at crowded living conditions and in schools or day care centers.

Treatment

Microscopic examination of the scrapings from the burrow sites can help in diagnosis. Scabies is mainly treatment by topical application of creams usually applied to the entire body from the neck to down in adults. In infants it is also applied to the face, neck and scalp. These medicines may need to be kept for around 8 to 14 hours before they are washed out. The medications that are prescribed for scabies are:

  • Permethrin 5% : This cream is applied twice with the second application after a week. It is a safe drug for children and adults and also safe for pregnancy or breastfeeding women.
  • Crotamiton :. This is applied once a day for two to five days can be used by all and with precautions in pregnant women.
  • Lindane : This is available as a shampoo, lotion or cream. This medication is contraindicated in children less than 2 years of age and pregnant or nursing women or people who have a weak immunity.
  • Ivermectin is a drug which can be used orally individually or along with topical medications for severe scabies.
  • Calamine lotions can be used for minor skin irritation.

Itching is treated with antihistamines but this only provides symptomatic relief for short periods The itching can be present even after the disease resolves due to the ongoing allergic response and antihistamines may need to be used as a short course thereafter.

More Related Topics