1. Gold Standard in Scabies
Dr. C Sakthivel

2. Scabies
The ectoparasites, scabies and pediculosis pubis are common causes of skin rash and pruritus worldwide.
Common public health problem in poor communities and developing countries.
Human scabies
Sarcoptes scabiei
30 day life cycle - within the epidermis
Pregnant female mites burrow into the skin and lay eggs. After two or three days the larvae emerge and dig new burrows. They mature, mate, and repeat this cycle every two weeks.

3. Scabies

4. Prevalence Scabies and pediculosis are common problem in the society
*Urban slum – 3.5%
It affects mainly pediatric population
**5.1 % to 22.4%
Rates of infestation in underdeveloped countries range from 4% to 100%.
Prevalence is higher in adults who are sexually active.
Crusted scabies —Norwegian scabies — is found in the
Immunocompromised (HIV),
Decreased sensory function (eg, people with leprosy),
Institutionalized patients.
*Indian Journal of Community Medicine
**Vol. 32, No. 1 ( )
Indian Pediatrics 2004; 41:

5. Life Cycle of Sarcoptes scabiei.
N Engl J Med 2010;362:

6. Transmission
Highly contagious and is spread from person to person by direct skin contact and fomites
Spread is related to
Overcrowded conditions,
Lack of public awareness
Delayed treatment of primary cases

7. Symptoms & signs Caused by the host immune reaction
Within two to six weeks of the initial infestation,
reinfestation symptoms within 48 hours.
Most common lesions
papules, vesicles, pustules, and nodules.
In adults,
Intractable pruritus, worse at night,
lesions in the web spaces, fingers, flexor surfaces of the wrists, axillae, and genital areas.
In infants and young children,
Face, head, neck, scalp, palms, and soles.

8. Typical childhood scabies –
Multiple pruritic papules, vesicles, and pustules.
Scabetic burrows are arrowed

9. Diagnosis A high index of suspicion
wide range of symptoms and presentations,.
Adults - rarely on the face and neck
children - commonly on the face and neck
A history of itching in family members
Lack of a history of itching in family members does not exclude scabies.
definitive diagnosis - microscopic
Identification of mites, eggs, or faecal pellets from burrow scrapings

10. Treatment If scabies is suspected, even without microscopic evidence
A variety of effective topical medications
permethrin,
malathion,
benzyl benzoate,
Lindane,
crotamiton.
Children should be given aqueous preparations
Must be applied correctly to maximise the success

11. Preferred treatment Topical agents such as lindane and permethrin
Permethrin 5% dermal cream
treatment of choice for scabies
in the United Kingdom, Australia, and the United States.
Most effective topical agent, acts at all stages of the parasite’s life cycle
Well tolerated, and has low toxicity
Lindane
Less effective than permethrin
has been withdrawn in many countries
aplastic anaemia and
potential neurotoxicity.
Benzyl benzoate
irritant
not recommended for children
J Am Acad Dermatol 2000;42:236-40
BMJ May 21; 330(7501): 1194–1198.

12. * Ivermectin is not approved for this indication by the Food and Drug Administration; there are insufficient data on the safety of ivermectin in pregnancy and in children younger than 5 years of age.

13. Comparison Parameter Permethrin Lindane Crotamiton safety Safe
Safety issues pediatric age
Safety issues in pediatric age
Efficacy
Effective than lindane 1% and crotamiton 10%
*Cure rate 98%
Effective
*Cure rate 84 %
effective *Cure rate 88%
*One month after application – Thomson Pharma, 2009

14. Comparison of the efficacy of topical 1% lindane vs 5% permethrin in scabies: A randomized, double-blind study
Resistance to lindane seems to be rising and there are reports of several clusters of patients with lindane-resistant scabies worldwide
Lindane has limitations for use in children and pregnant women
Several reports of central nervous system toxicity, convulsions, and even death following accidental ingestion, overuse, or even a single application of lindane
There is a need for a more effective and safer medication for the treatment of scabies
Indian J Dermatol Venereol Leprol 2006;72:33-6

15. Permethrin Paraciticidal Mechanism of action
Acts on the nerve cell membrane to disrupt the sodium channel, and interrupting signals travelling between the brain and the muscles. The lice/parasites become paralyzed and die because they are unable to breath. Permethrin has ovicidal activity and can also kill the nits or eggs of the parasites.
Pharmacokinetic
very low dermal absorption and are quickly metabolized to inactive metabolites that are excreted in the urine within a week.

16. Permethrin cream Permethrin 5 % cream Indication:
For the treatment of infestation with Sarcoptes scabiei (scabies)
Dosage and administration
Adults and children: Thoroughly massage permethrin cream into the skin from the head to the soles of the feet.
Scabies rarely infests the scalp of adults, although the hairline, neck, temple, and forehead may be infested in infants and geriatric patients.
Usually 30 grams is sufficient for an average adult. The cream should be removed by washing (shower or bath) after 6 to 14 hours.
Infants should be treated on the scalp, temple and forehead.
ONE APPLICATION IS GENERALLY CURATIVE.

17. Postscabietic pruritus
Not uncommon
last for 2 to 4 weeks after successful treatment
Attributed to the hypersensitivity response to dead mites and their body parts
Symptomatic relief
Oral antihistamines
topical corticosteroids
Oral steroids (severe cases)

18. Key points to reduce transmission
Fomites, clothes that have been worn the day before treatment and linens ideally should be washed in hot water and dried on high heat.
All sexual and close personal contacts should be treated even if asymptomatic
Scabies mite cannot survive longer than 4 days without skin contact;
if hot water is not available, all linen and clothing should be placed into plastic bags and stored for 5 to 7 days to reduce transmission.
“Resistant” scabies - due to reinfestation

19. Review article Clinical manifestations of scabies infection
Lancet Infect Dis 2006; 6:769–79

20. Review article Scabies: a ubiquitous neglected skin disease
Children, especially in poor countries, frequently present with scabies superinfected by group A streptococci or Staphylococcus aureus, which should be treated first.
Lancet Infect Dis 2006; 6:769–79

21. Review article Scabies: a ubiquitous neglected skin disease
Treatment guidelines in early childhood, and during pregnancy and lactation
Lancet Infect Dis 2006; 6:769–79

22. USP Permethrin cream One application is curative
Safe & effective than lindane
extremely low mammalian toxicity
Can be used in all ages
permethrin is approved for infants 2 months of age or older
USFDA Approved in 1989
Combination with ivermectin in crusted scabies

23. Thank You