Scabies Disease

Scabies

• Infectious disease caused by Sarcoptes scabiei mites, associated with severe itching
• Incubation period: 2-3 weeks
• Mode of infection: close contact with patients, indirect contact through clothes or bedding, contact with infected animals
• Clinical features:
  • Severe itching, especially at night
  • Skin-colored or grey curved ridges (burrows) on the skin
  • Papules, vesicles, pustules, and scratch marks
• Sites affected: various parts of the body, including infants and animals
• Clinical varieties: scabies in infants, scabies in the clean, scabies incognito, nodular scabies, animal scabies, Norwegian scabies

Complications of Scabies

• Secondary bacterial infection
• Eczematous changes
• Acarophobia

Diagnosis

• Itching mainly at night
• Presence of burrows
• Distribution of lesions
• Contact cases within the family
• Demonstration of parasite under microscope

Differential Diagnosis

• Papular urticaria
• Prurigo
• Eczema

Treatment

• Prophylactic measures: early diagnosis, treatment, disinfection, and treatment of family members and infected animals
• Topical treatment:
  • Benzyl Benzoate 25%
  • Gamma benzene hexachloride 1%
  • Crotamiton 10%
  • Permethrin 2.5-5%
• Systemic treatment:
  • Ivermectin
  • Antihistamines for itching
  • Antibiotics for secondary bacterial infection
  • Intralesional steroid injection for post-scabetic nodules

Pediculosis

• Humans are parasitized by two species of lice: Pediculus humanus and Pthirus pubis

Pediculosis Capitis

• Common infestation transmitted by sharing head-covers, combs, or brushes
• Common among school children, especially girls
• Main symptom: pruritus
• Secondary bacterial infection is common due to scratching
• Diagnosis: by finding parasites or their eggs (nits)
• Treatment:
  • Permethrin 1%
  • Malation 0.5%
  • Gamma benzene hexachloride 1%
  • Crotamiton 10%
  • Removal of nits
  • Antibiotics for secondary infection

Pediculosis Corporis

• Lice live in seams of clothing or bedding
• Generalized itching, erythematous macules, or urticarial wheals due to punctures
• Secondary infection is common
• Diagnosis: by finding lice or nits in clothes or beddings
• Treatment:
  • Destruction of lice by boiling and ironing of clothing and bedding
  • Malathion dusting powders for clothing
  • Thorough bath with soap and water for the patient

Pediculosis Pubis

• Contracted chiefly by adults through sexual intercourse, and occasionally from bedding
• Affects pubic area, rarely axilla, thigh, abdomen, and eyelashes
• Itching is the main symptom, and secondary infection may be present
• Treatment:
  • Permethrin 1% for 10 minutes
  • Gamma benzene hexachloride 1% for 8 hours