Today is our topic of discussion Contact Diseases
Contact Diseases
Definition:
Contact/contagious diseases are those communicable diseases that are acquired by the direct contact of the infected person. Example-
Disease
Scabies Ringworm
Vaginal candidiasis
Leprosy
Trachoma
Causative agent
Sarcoptes scabii
Tinea
Candida albicans
Mycobacterium leprae
Chlamydia trachomatis
Scabies
Definition:
Scabies is a contagious skin disease caused by a species of mite, called Sarcoptes scabiei.
Epidemiology:
Scabies is endemic all over the world & the incidence is high in Bangladesh.
Agent:
Sarcoptes scabiei.
Host:
Scabies can affect all regardless of age, gender, race, social class, or personal-hygiene habits.
Environment:
Common in nursing homes, hospitals, hostel, people living with insanitary and poor housing conditions. Also spread among household members and sexual partners.
Reservoirs:
Patients
Mode of transmission:
1. Personal contact – Sleeping & playing together.
2. Sharing of utensils – Towels, bed sheets and personal belongings
3. Causal contact – Shaking hand, handling a patient
Incubation period:
2 to 6 weeks
[IP can be as little as 1 to 4 days in people who are sensitized by prior exposure]
Period of communicability:
Can spread to another person before symptoms appear. Patient is infective, until cured completely.
Clinical feature:
1. Itching: Intense, especially at night (‘pleasant itching’) along with characteristic burrow and vesicular rash. Common sites are-
a. Between the fingers (finger webs) & wrist (usually flexor surface)
b. Elbow, axilla & shoulder blades ads floor
c. Inguinal folds, penis & popliteal folds
d. Nipple, waist & buttocks
2. The head, face, nack, palms and soles are not usually involved in adults but can affect infants and young children.
3. Tiny burrows containing mites and their eggs sometimes are seen on the skin.
4. Secondary skin infection may be associated
Life cycle:
Adult mites burrow into the upper layer of epidermis → Females lay eggs in the burrows → Eggs hatch after 3-4 days into larvae, which dig new burrows closer to the skin surface → The larvae mature into adult mites in about 4 days → Adults can then either stay in that host or be scratched off and transmitted to a new host → Adult females can live in the host for up to a month.
Diagnostic test:
Scraping out of the mite from a burrow & demonstration of eggs under microscope.
Treatment:
Scabicidal drugs:
a. 5% permethrin cream
b. 25% Benzyl benzoate emulsion (Ascabiol)
c. Monosulfiram 25% lotion (Tetmosol)
d. Crotamiton (10%) cream or lotion
e. Tab. Ivermectin (6 mg): Used only when topical medications failed or hypersensitivity. The dose is 1 tablet for 30 kg, 2 tablets for 60 kg body weight. Contraindicated in pregnancy, admos lactation and children < 5 years.
Anti-histamine (pruritus):
Chlorpheniramine or cetirizine.
Antibiotic (secondary skin infection):
Cephradine or flucloxacillin
Method of application of topical preparation:
Applied to the whole body from neck down & left for 24 hours and then washed off. In children and young infants, it should also be applied in the affected areas of head, neck & face, but caution applied to put the fingers in the mouth, conjunctiva & nostril.
Prevention & control measures:
1. Avoiding close skin-to-skin contact with patients until treated.
2. If one member of household suffers with scabies, all household members, sexual partners and close contacts should be treated simultaneously.
3. Hospital staffs should use gloves/gowns when treating patients with suspicious rash or itching.
4. Wash & clean all clothes used by the patient with soapy water, then dry in direct sunlight.
5. Improvement of personal hygiene & avoiding crowded living conditions.
6. Making starve the mites: Placing items that can’t be washed, in a sealed plastic bag for 7 days.
7. Children should avoid school until the day after treatment.
Complication:
1. Secondary bacterial infection at the itching site
2. Acute glomerulonephritis
See also :