Scabies:
Scabies is a highly contagious skin infestation caused by the mite Sarcoptes scabiei.
The female mite burrows into the stratum corneum (the outermost layer of the skin) to lay eggs, causing intense itching and a characteristic rash. It’s a significant public health problem, particularly affecting populations living in close proximity or with compromised hygiene.
Etiology
The causative agent is the Sarcoptes scabiei mite. The female mite burrows into the epidermis, depositing eggs and feces along its pathway. The mite’s saliva and fecal matter trigger an inflammatory response in the host, leading to the characteristic symptoms.
Forms and Routes of Transmission:
Scabies is transmitted primarily through direct, prolonged skin-to-skin contact. This is most common during sexual activity, close physical contact (e.g., hugging, cuddling, wrestling), or sharing bedding, clothing, or towels with an infested person. Transmission can also occur indirectly via contaminated fomites (inanimate objects), although this is less frequent than direct contact. The mites cannot survive for extended periods away from a human host.
Incubation Period:
The incubation period (the time between infestation and the appearance of symptoms) varies, but it typically ranges from 4 to 6 weeks for a primary infestation. In individuals previously exposed to scabies, symptoms may appear more rapidly (within 1-4 days) due to a hypersensitivity reaction.
Types of Scabies:
There are two main types of scabies:
- Crusted scabies (Norwegian scabies): This is a severe form characterized by thick, crusted lesions containing a large number of mites. It’s highly contagious and commonly seen in immunocompromised individuals.
- Typical scabies: This is the most common form, characterized by intense itching and a papular rash.
Clinical Features
- Intense nocturnal pruritus (itching): The itching is often worse at night.
- Papular rash: Small, raised, itchy bumps (papules) that may be clustered or widespread.
- Linear burrows: Thin, slightly raised lines in the skin representing the mite’s burrow. These are often found on the hands, wrists, and interdigital webs.
- Excoriations: Scratches and abrasions resulting from intense itching.
- Nodules: Small, firm lumps that may be present.
- Secondary bacterial infection: Infection can occur due to scratching and breaking the skin’s integrity.
- Distribution: Classic scabies tends to favor areas of the body with thin skin, such as the wrists, hands, interdigital spaces, elbows, and axillae. It can also affect the groin, buttocks, and genitalia. Crusted scabies can have a more widespread distribution.
- Intense itch: this is present in typical scabies
Definitive Diagnosis and Investigations:
The diagnosis of scabies is primarily clinical, based on the characteristic rash, intense itching, and burrow identification. However, microscopic examination of skin scrapings can confirm the presence of the mite, its eggs, or fecal matter under a microscope (this is known as a skin scraping).
Management:
Aims: The primary aims of scabies management are to eradicate the mites, relieve symptoms (itching), prevent complications, and prevent transmission.
Medical Management:
- Scabicides: Topical scabicides are the mainstay of treatment. Common options include permethrin cream (5%), malathion lotion (0.5%), ivermectin (oral), and lindane (less commonly used due to potential neurotoxicity). Treatment typically involves applying the scabicide to the entire body from the neck down, leaving it on for the recommended duration (usually overnight), and then washing it off. A second application might be necessary after a week.
Nursing Care:
- Education: Provide thorough patient and family education about scabies transmission, treatment, and prevention.
- Hygiene: Teach meticulous hygiene practices, including frequent handwashing and cleaning of bedding, clothing, and towels.
- Symptom management: Help patients manage itching with appropriate strategies, such as cool compresses, calamine lotion, and antihistamines.
- Monitoring: Monitor for signs of secondary infection, such as increased redness, swelling, pain, or pus.
- Medication Administration: Administer and monitor medication as prescribed.
Prevention:
- Avoid close contact: Limit skin-to-skin contact with individuals known to have scabies.
- Good hygiene: Practice frequent handwashing and avoid sharing personal items such as towels, bedding, and clothing.
- Prompt treatment: Seek prompt medical attention if scabies is suspected.