Stopping the Itch: Scabies in Healthcare Settings
Introduction
Mites are tiny, tick-like arthropods that usually cannot be seen by the human eye. These tiny arthropods generally do not affect people, but there are a few that can cause irritation in humans. House dust mites, for example, are a common allergen in indoor settings. Chiggers and itch mites that are found in grass, leaves, and hay can cause skin rashes if you come in contact with them. Chicken, rodent, and bird mites are found on different animals, causing conditions like mange, and can also cause rashes on humans. However, these mites do not live long on human skin so these rashes heal on their own and ointments can be used to relieve the itchiness. (1, 2) While these mites are typically harmless, the mite that causes scabies can be a healthcare concern.
Causative agent and epidemiology
Human scabies is a parasitic infection, sometimes called a parasitic infestation, caused by a tiny mite called Sarcoptes scabies var. hominis. It is estimated that over 400 million people each year are affected by scabies globally. In 2017, scabies was added to the World Health Organization's Neglected Tropical Diseases category, due to it being a common skin condition in hot, tropical and low income areas. While not as common in high income countries, scabies cases can occur in healthcare and other institutional settings, like jails and shelters. (3, 4)
Scabies is spread by direct skin-to-skin contact. This means that children, healthcare workers, family members, and other individuals that have close and prolonged contact with someone who has scabies are at most risk for developing the infection. Contaminated clothing and bedding can also spread the disease. For typical scabies infection, ten to fifteen mites can cause an infection. (3, 4)
Symptoms
Scabies can be divided into two presentations, typical and crusted scabies.
Typical scabies presents with extreme itchiness that worsens overnight. Red lines and bumps occur on the hands, arms, legs, and around the belt area. Rashes may also be present on the breasts and male genitalia. In young children, rashes may also appear on the scalp, face, the soles of feet, and palms. (3, 4)
Crusted scabies, also known as Norwegian scabies, occurs in people who are immunocompromised, meaning they have weakened immune systems. Crusted scabies generally does not present with itchiness and is instead characterized by dry, thick and scaly skin caused by millions of mites. Areas affected can include the palms, the soles of feet, and earlobes. (3, 4)
Diagnosis and treatment
While there are multiple techniques to diagnose scabies, recognizing the rash and identifying if someone has had close contact with an infected person is most important in timely diagnosing the skin condition and preventing its spread. Other common techniques include microscopy of skin scrapings and dermoscopy, which is a small handheld magnifying device used to look closely at a person’s skin.
One of the main drugs used to treat scabies is ivermectin. It is generally used alone for typical presentations and in combination with other medicines, like permethrin or salicylic acid, for crusted scabies. These treatments may last a few weeks as they do not target scabies eggs, so longer treatment ensures newly hatched scabies mites are killed.
Sometimes scabies infections reoccur after treatment due to continued contact with people who have the disease and have not been treated or because their clothing/bedding has not been properly cleaned. Treating contacts, even if they do not have symptoms, is important in limiting scabies spread. (3,4 and 5)
Complications
Scabies infections can cause a few different complications. Most commonly, scabies can cause insomnia and prolonged itchiness after treatment. Secondary skin infections like impetigo, a bacterial skin infection, can also occur from scratching at the affected skin. These infections can worsen to cause abscesses or septicemia. The kidneys can also be damaged in cases of post-streptococcal glomerulonephritis.(3, 4)
Prevention in healthcare settings
In healthcare settings, being able to recognize the rash or suspect scabies in cases of unknown rashes is important to timely diagnosing and treating infected patients. This requires institutions to invest in continuously educating their staff regarding presentation, treatment, and prevention of scabies and other conditions that cause rashes. (3,4, 5, 6)
Since scabies is spread from skin to skin contact, contact precautions should be used for patients with scabies infections. This typically includes using PPE (personal protective equipment) like gowns and gloves when performing patient care. In addition, dedicated or disposable patient items like stethoscopes should be used. Contact precautions can be stopped after twenty-four hours of effective treatment. Treating close contacts and thorough environmental cleaning is also important to preventing the spread of scabies in healthcare settings. (3,4, 5, 6)
Sources
1. https://dph.illinois.gov/topics-services/environmental-health-protection/structural-pest-co ntrol/mites-affecting-humans.html
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