Scabies
Causative organism: Sarcoptes scabiei var. hominis (Itch mite).
Highly contagious disease
spreads in households and environments where there is intimate personal contact
Transmitted through infected clothes, linens and sexual contacts.
PATHOGENESIS
CLASSIFICATION
Classical
Nodular scabies
Crusted (Norwegian) scabies
Bullous scabies
PREDISPOSING FACTORS
Lack of hygiene
Low socioeconomic conditions
Close physical contacts
Immunocompromisation
Vagabond
Old age
Hospital stay
Down syndrome, Organ transplant, Leukemia, AIDS patients
CLINICAL FEATURES
Pathognomonic lesion:
Burrow which is slightly elevated, greyish and tortuous lines. Vesicle or pustule containing the mite may be found found at the end of the burrow
(Definition: a linear or curvilinear papule, caused by a burrowing scabies mite)
Papules, excoriations, bulla, crust and lichenification occurs.
Pruritus is prominent symptom which is severe and usually more intense in the night.
Even after successful treatment, itch can continue and occasionally nodular lesions persist.
SITES
Finger webs
Wrists
Axilla
Nipple and Areola
Umbilicus
Lower abdomen
Genitalia
Buttock
Scrotum and penis
Face and scalp in infant
Around and underneath nails
Involvement of the genitals in males and of the nipples in females are pathognomic.
COMPLICATIONS
Local:
Secondary bacterial infections – impetigo, folliculitis, furunculosis.
Eczematization
systemic: acute glomerulonephritis
INVESTIAGATIONS
The diagnosis is made by identifying the scabietic burrow and visualizing the mite (by extracting with a needle under microscope or using a dermatoscope).
Burrow is detected with gentian violet and then the organism is isolated with needle or scalpel and visualized under microscope.
TREATMENT
General measures
Counselling and reassurance
Maintenance of personal hygiene
Treatment of family members and close contacts at a time.
Washing of clothes and beddings.
Specific measures
Topical therapy
1.5% permethrin cream – 2 applications 1 week apart., Apply all over the body (except head and face in adults) and keep it for 8 to 12 hours. Then wash off .
All family members and physical contacts need to apply in the same way at same time.
2.25% Benzyl benzoate
3.Crotamiton 10% cream
4.10% precipitated sulphur
5.Malathion
6.Lindane
7.Monosulfirum
Systemic therapy
Ivermectin: single dose in case of severe infestation and in immunosuppressed patients.
3. Highly contagious disease
spreads in households and environments
where there is intimate personal contact
Transmitted through infected clothes, linens
and sexual contacts.
4. PATHOGENESIS
Parasite infestation occurs by close ontact or
clothes or fomites of infected person
Mites form burrow and lays eggs
Sensitization occurs
Clinical lesions occurs
6. PREDISPOSING FACTORS
•Lack of hygiene
•Low socioeconomic conditions
•Close physical contacts
•Immunocompromisation
•Vagabond
•Old age
•Hospital stay
•Down syndrome, Organ transplant, Leukemia,
AIDS patients
7. CLINICAL FEATURES
• Pathognomonic lesion:
• Burrow which is slightly elevated, greyish and
tortuous lines. Vesicle or pustule containing the
mite may be found found at the end of the burrow
(Definition: a linear or curvilinear papule, caused by a
burrowing scabies mite)
8.
9. •Papules, excoriations, bulla, crust and
lichenification occurs.
•Pruritus is prominent symptom which is
severe and usually more intense in the night.
•Even after successful treatment, itch can
continue and occasionally nodular lesions
persist.
14. •Systemic:
•Acute glomerulonephritis –
when the lesions are secondarily infected by β-
haemolytic streptococcal strains of 49, 55, 57, 60 and
M type 2, then there is deposition of Ag-Ab in the
glomerular basement membrane causing
inflammation resulting in Acute glomerulonephritis.
15. INVESTIAGATIONS
•The diagnosis is made by identifying the scabietic
burrow and visualizing the mite (by extracting with
a needle under microscope or using a
dermatoscope).
•Burrow is detected with gentian violet and then the
organism is isolated with needle or scalpel and
visualized under microscope.
16. TREATMENT
•General measures
1. Counselling and reassurance
2. Maintenance of personal hygiene
3. Treatment of family members and close
contacts at a time.
4. Washing of clothes and beddings.
17. • Specific measures
1. Topical therapy
5% permethrin cream – 2 applications 1
week apart., Apply all over the body
(except head and face in adults) and keep it
for 8 to 12 hours. Then wash off .
All family members and physical contacts
need to apply in the same way at same
time.