Clinical Overview of Crusted scabies

Overview

Crusted scabies (formerly known as Norwegian scabies) typically presents with hyperkeratotic plaques that may be fissured and can have associated erythema. Patients with crusted scabies may not show the usual signs, symptom, or lesion distribution seen in classic scabies. Patients may not have the characteristic rash and pruritus (itching) may be mild or absent. Large numbers of scabies mites and eggs—up to two million, may be present on a single patient. Patients with crusted scabies should receive quick and aggressive medical treatment for their infestation because of the risk of complications, such as sepsis, and to prevent outbreaks of scabies.

Risk factors

People who have an increased risk of developing crusted scabies include:

• The elderly
• Persons with immunocompromise, such as people living with HIV/AIDS
• Persons with conditions that prevent them from itching and/or scratching (spinal cord injury, paralysis, loss of sensation, severe mental or behavioral health conditions).

Prevention

To prevent outbreaks after the diagnosis of crusted scabies, take immediate steps for infection control and treatment.

Detection

Identify close contacts to persons with crusted scabies. Close contacts, including household members, sexual contacts, and other close personal contacts should be treated as soon as possible after the diagnosis is made.

Diagnosis

• Early diagnosis and appropriate treatment of crusted scabies is key to preventing further scabies infestations.
• Only a healthcare professional can diagnose scabies and prescribe the appropriate treatment.

Infestation control

• Wash bedding, clothing, and towels in hot water and dry in a hot dryer. Temperatures in excess of 50°C or 122°F for 10 minutes will kill mites and eggs.
• Dry-clean or seal items that can't be washed in a sealed plastic bag for at least 72 hours to one week.
• Avoid close contact with others until therapy is completed.
• Notify all people who had close contact with the patient and encourage them to seek treatment.
• Rooms used by a patient with crusted scabies should be thoroughly cleaned and vacuumed after use.
• Environmental disinfestation using pesticide sprays or fogs generally is unnecessary and discouraged.
• Discarding mattresses is generally unnecessary.

Crusted scabies is very contagious due to the large number of mites present with an infection. Outbreaks of scabies are more common with crusted scabies. It spreads easily through brief, direct contact and by contact with infested clothing, bedding, and furniture. Treat crusted scabies aggressively to prevent outbreaks, especially in group facilities or institutional settings, e.g., assisted living facilities, hospital settings, correctional facilities, etc. To help control an outbreak of crusted scabies, contact your local or state health department.

Treatment

Treat patients with crusted scabies with both prescription oral and topical medications. First line therapy for crusted scabies includes topical permethrin and oral ivermectin. Duration of treatment depends on the severity of the disease. See "Clinical Care of Scabies" for specific treatment regimens.