Scabies Diagnosis, Transmission, and Treatment in a Family

(i) Organism Causing Scabies in Humans

Scabies in humans is caused by the microscopic mite, Sarcoptes scabiei var. hominis. This obligate human parasite burrows into the outermost layer of the skin (stratum corneum) to live, feed, and lay eggs. The intense itching and rash associated with scabies are primarily due to an allergic reaction by the host to the mites, their eggs, and their fecal matter.

(ii) Factors Involved in the Transmission of Scabies in a Family

Scabies is primarily transmitted through direct, prolonged skin-to-skin contact. In a family setting, several factors contribute to its rapid spread, especially among vulnerable members:

• Close Physical Contact: Living in close quarters, typical of joint families, facilitates prolonged skin-to-skin contact during daily activities, sleeping, hugging, and caregiving. This is particularly relevant for the infant, who has constant contact with caregivers, and for the senior citizens.
• Shared Living Spaces and Items: While less common than direct contact, sharing bedding, clothing, towels, and furniture can also contribute to transmission, especially if individuals have crusted scabies with a higher mite load.
• Delayed Diagnosis and Treatment: Symptoms may take 4-8 weeks to appear after initial infection. During this asymptomatic period, an infested individual can unknowingly transmit the mites to others in the family.
• Vulnerable Immune Systems: Senior citizens may have weaker immune systems, making them more susceptible to infestation and potentially leading to more severe forms like crusted scabies, which is highly contagious. Infants also have developing immune systems, increasing their susceptibility.
• Antenatal Women and Increased Risk: While not directly increasing transmission, the physiological changes and potential for immunosuppression during pregnancy can influence the severity and management strategies.
• Lack of Awareness: Insufficient knowledge about scabies transmission and prevention within the family can lead to inadequate hygiene practices and delayed seeking of medical attention.
• Crowded Conditions: High population density within a household, as often seen in joint families, significantly increases the likelihood of transmission.

(iii) Plan for Treating Scabies in This Family

A comprehensive treatment plan for this family must consider the unique vulnerabilities of senior citizens, antenatal women, and a one-month-old infant, focusing on simultaneous treatment, environmental decontamination, and follow-up.

1. Simultaneous Treatment of All Family Members:

This is crucial to break the cycle of transmission. All individuals living in the household, including asymptomatic ones, must be treated at the same time.

2. Pharmacological Treatment Options:

The choice of scabicide will depend on the age and physiological state of each family member, adhering to safety guidelines.

• For Adults (including Senior Citizens, excluding Antenatal Women):
  • Permethrin 5% Cream: This is generally the first-line treatment. It should be applied to the entire body from the neck down (including scalp, face, and ears in infants and elderly), left on for 8-14 hours (typically overnight), and then washed off. A second application after 7-14 days is often recommended to kill newly hatched mites.
  • Oral Ivermectin: May be considered for severe cases (like crusted scabies) or when topical treatment is difficult or contraindicated. However, caution is advised for the elderly due to potential side effects and drug interactions.
  • Benzyl Benzoate Emulsion (10-25%): An alternative topical option, applied similarly to permethrin.
• For Antenatal Women:
  • Permethrin 5% Cream: Generally considered safe for use during pregnancy and lactation. It should be applied as directed, with careful attention to proper technique. Oral Ivermectin is generally contraindicated during pregnancy and breastfeeding.
• For the One-Month-Old Infant:
  • Permethrin 5% Cream: Considered the safest topical treatment for infants over 2 months. For a one-month-old, use needs to be under strict medical supervision. The cream should be applied carefully to the entire body, including the face, scalp, and neck, avoiding eyes and mouth. Manual removal of crusts (if present) before application can improve efficacy.
  • Sulphur Ointment (5-10%): An alternative for infants and young children, applied nightly for 3-5 nights.
  • Careful application: Ensure the cream is reapplied to hands if washed off during the treatment period.

3. Non-Pharmacological Measures and Environmental Decontamination:

These are critical to prevent re-infestation.

• Washing Contaminated Items: All clothing, bedding, and towels used by infested individuals for up to 72 hours prior to treatment should be machine washed in hot water (at least 60°C) and dried in a hot dryer cycle or direct sunlight.
• Sealing Non-Washable Items: Items that cannot be washed (e.g., stuffed toys) should be placed in sealed plastic bags for at least 72 hours (or up to a week) to starve the mites.
• Vacuuming: Thoroughly vacuum furniture, carpets, and rugs. Dispose of the vacuum bag immediately.
• Hygiene Education: Educate all family members on proper hygiene, the importance of avoiding close contact with infested individuals until treatment is complete, and the need for prompt treatment if symptoms recur.
• Clipping Fingernails: Especially for children and senior citizens, clipping fingernails can reduce excoriation and secondary bacterial infections.

4. Management of Symptoms and Complications:

• Itch Relief: Antihistamines (with caution in infants and the elderly), topical corticosteroids, or pramoxine lotion can be used to manage persistent itching, which can continue for 1-2 weeks even after successful eradication of mites due to the allergic reaction.
• Treating Secondary Infections: If bacterial infections (e.g., impetigo) have developed due to scratching, appropriate antibiotics may be prescribed.

5. Follow-up:

Regular follow-up appointments are essential to monitor treatment efficacy, address persistent symptoms, and detect any re-infestation.