Scabies

Definition/diagnostic criteria Scabies is a contagious parasitic infestation characterised by intense itching, especially at night, and a rash that may appear as raised spots or burrows caused by tiny mites laying eggs in the skin.

Scabies usually spreads across the body, excluding the head, but may involve the head and neck in older people, young children and those with weakened immune systems.

Epidemiology Scabies is common in the UK, with a significantly higher infestation rate among females and in the 10-19 age group.

Diagnosis Diagnosis is primarily clinical, based on the patient’s history and skin examination.

• A person with scabies typically has a mixture of scratch marks, tiny red spots, and crusty sores.
• The diagnosis can be aided by dermatoscopy, the ink burrow test, and microscopic examination of skin scrapings.
• Scabies burrows are most commonly found in skin folds, such as between fingers and toes, on wrists, ankles, groins, and breasts​​​​​​.

Treatment Treatment involves applying a parasiticidal preparation to the entire body. Key treatments include permethrin cream and malathion liquid. All close contacts must be treated simultaneously to prevent re-infestation. Treatment should be repeated after a week. If the initial treatment fails, a different preparation may be used.

Secondary bacterial infections should be treated with antibiotics​​​​.

Prognosis Scabies will persist indefinitely without treatment but has a high cure rate with correct treatment application. Post-treatment itching may continue for up to two weeks but does not indicate treatment failure. Persistent itching for more than six weeks might suggest treatment failure or re-infestation​​​​.