PRESENTER

DR. MD. ABDAL MIAHASSISTANT PROFESSOR

DERMATOLOGY & VENEREOLOGYMYMENSINGH MEDICAL COLLEGE,

MYMENSINGH

CHAIRED BY

DR. MD. SHAHAB UDDIN AHMED CHOWDHURYAssociate Professor & Head

Department of Dermatology & VenereologyMymensingh Medical College, Mymensingh.

TODY’S TOPIC IS

IVERMECTIN

USE IN SCABIES

Source: American Family Physician (Review Journal)Sept 15, 2003, V-68, P-1089-92

Scabies is a skin disease caused by infestation with the mite female gravid sarcoptes scabiei var hominis. Scabies has been a problem for humans since before the first millennium and was reported by the earliest writers who described mankinad’s health problems. It is estimated that there may be 300106 cases of scabies worldwide each year. Mostly, scabies is treated with topical scabicides, which needs to be used over whole or nearly whole skin surface, which is a difficult process.

INTRODUCTION

So, non compliance or improper use of

topical scabicides can result in scabies

as a public health problem. So, the time

honored demand was for systemic

alternative. Now, oral ivermectin has

appeared as an effective and cost-

comparable alternative to topical agents

in the treatment of scabies infection.

DIAGNOSIS OF SCABIES

The diagnosis of scabies usually is

clinical but may be confirmed by

microscopic identification of female

mite, eggs and scybala in skin

scrapings.

Key points for the diagnosis of scabies

are the following:

1. Morphology of skin lesions (i.e. type of eruptions)–

Pathognomonic lesion– Linear burrows.

Nonspecific- Papular or papulovesicular or vesiculo-pustular lesions.

Excoriations and ulcerations.

Urticarial lesions- rarely.

2. Typical distribution–

Common sites (irrespective of age and sex).

Finger-webs, flexor surfaces of wrists, flexor surfaces of elbows, axillae, umbilicus, waistband, gluteal crease.

Male- genitalia

Female- breasts (Areola and Nipple)

Infants and young children-

Scalp, face, palms and soles

3. Pruritus– Usually intense, disproportionate to the amount of eruptions, worse at night and pleasant in quality.

4. Positive history in skin contacts.

5. Definitive diagnosis rests on identification of the mites or its products.

Useful diagnostic methods:a) Direct examination of skin scrapings

under low power objective.

b) Dermoscopy.

c) PCR.

TREATMENT

A. Treatment of patients: It includes

i) Treatment of complications

ii) Symptomatic treatment and

iii) Specific treatment with scabicides.

Topical and systemic scabicides:a. Topical scabicides include

– Precipitated sulfur 6% or 7% in petroleum jelly– Benzyl benzoate emulsion 25%– Monosulfiram- a 25% solution– 1% Gamma benzene hexachloride (lindane)– Malathion 0.5%– Crotamiton 10%

b. Systemic scabicide- oral ivermectin 200 gm/kg- Single dose, may have to be repeated.

B. Treatment of contacts.C. Trcatment of house-hold utensils.

IVERMECTIN First it was developed in the 1970s as a

veterinary treatment for animal parasites. It is a member of a family of macrolytic

lactones, the avermectins. It has broad spectrum activity against

parasites such asFDA approved- Strongyloidiasis

Onchocerciasis.Not FDA approved-Filariasis

Cutaneous larva migrans.Scabies.Pediculosis etc.

An estimated 6 million people world-wide have taken ivermectin for various parasitic infestations.

Since 1993, it has been successfully used in different countries to treat human scabies that is resistant to treatment.

Some of the study results are shown below:

Study No. of patients Cured (%) Not Cured (%)

1 26 96.15 3.85

2 11 100 00

3 100 83 17

4 11 (with AIDS) 70*

>90**

30*

<10**

Many other studies done by different

groups such as Glaziou P et al, Dunne

CL et al, Kar SK et al, Shouela EN et

al, Madan V et al, Usha V et al also

confirmed the efficiency of ivermectin

as a treatment of scabies infection.

SAFETY OF IVERMECTIN:

Adverse effects such as anorexia, nausea,

vomiting, rash, headache, dizziness,

arthralgia, itching, eosinophilia,

abdominal pain, fever, tachycardia etc

may occur but occur very infrequently. No

serious drug-related adverse events or

significant drug interactions have been

reported.

But its safety in young children and

pregnant women– not established.

A comparison of ivermectin with 5% permethrin is shown below:

Drug Efficacy Adverse effects

Cost Use in children

In pregnancy

Nursing women

Ivermectin 83-100% anorexia, nausea,

vomiting, rash,

headache, dizziness, arthralgia,

itching, eosinophilia, abdominal pain, fever, tachycardia

etc

Tk. 40*

Tk. 80**

Safety not proved in children

<15 kg or <5 years

C Not recommended

Permethrin 91-98% Pruritus, burning, stinging

Tk. 40*

Tk. 80**

Safe in children

2 months

B Not recommended

Superiority of ivermectin over others:

1. Easy route of administration– oral.

2. Dose convenience– only single dose.

3. Efficacy– very high- 98-100%.

4. Safe– very infrequent side effects and not a single major adverse event over 6 million users.

5. Cost effective.

So, many authors and publications

consider it to be the treatment of choice.

CONCLUSION

Oral ivermectin, because of its single oral

dosing, very high efficacy and safety, and low

cost, may replace the other topical agents in

the treatment of scabies. It may be particularly

useful in the treatment of severely crusted

scabies lesions in immunocompromised

patients or when topical therapy has failed or

application of topical agents is logistically

difficult (e.g. large institutional outbreaks or

mentally impaired patients).

MESSAGE

We know the cause

We know the mode of transmission

We have multiple weapons to fight against this mite.

But this mite is winning the battle affecting 300 million peoples each year around the globe.

So, IVERMECTIN may be the best weapon

to win this battle.