Scabies
What is Scabies?
Scabies is a skin problem characterized pus-filled (purulent) blisters, papules or bumps on the surface of the skin. These bumps are formed by the bite of tiny skin mites which are about 0.4mm to 0.8mm in size and barely visible to the eye. The mites bite the skin and then lay their eggs in the burrows thus formed. The bumps are itchy and in fact, the word scabies is a modified version of the Latin term scabere which means “to scratch”.
Symptoms of Scabies
The parts of skin affected by Scabies are:
a) Warm parts of the skin like genitals and nipples, especially if tight undergarments are used
b) Skin folds like under the breasts and buttocks, underarms, inner surface of elbows
c) On the beltline
d) On wrists (when tight wristwatches are used)
e) The skin under rings worn perpetually or between fingers
f) On palms, soles of feet, scalp (in children).
The common symptoms of scabies are:
1) Severe itching – which seems more intense in heat or at night
2) Dark-red purulent (filled with pus) bumps or blisters which are called pustules
3) Sores or broken pustules where the person scratches
4) Sleeplessness caused by the constant itching sensation
5) Irritability due to lack of sleep and itching
6) Impetigo – this infection (secondary) occurs in the scratched areas and is caused by the staphylococci or streptococci bacteria.
The bumps can be either localized around wrists and between fingers; or can be more like thin, dark-red lines on the wider areas of skin.
Besides the common symptoms, the additional symptoms of Norwegian Scabies or Crusted Scabies are:
1) Crusty or scaly blisters covering larger areas of skin (scabbed appearance)
2) Severe itching
3) Thickened skin in the affected areas
Diagnosis of Scabies
The incubation period of the mites is about 8 weeks. Until then, the bumps 
look like ordinary pimples, acne or even eczema and not scabies infection. One indication specific to scabies is the infection in between the fingers. This is a characteristic only of scabies infection and not indicative of other skin disorders. The first stage of diagnosis would be a through physical examination, and more so in the crevices or skin folds and between fingers. Once, scabies is suspected, the tests carried out for confirmation of diagnosis are:
Staining of skin: To carry out this test, with the help of a swab a little ink or a solution of tetracycline is first applied on the skin in the affected area. After a while it is wiped off with a pad moistened with alcohol. An S-shaped or zigzag mark will be visible on the skin indicating scabies.
Microscopic examination: At the same time as staining test, scrapings of the surface of affected skin are collected. These are tested with mineral oil or glycerol, and would give a positive result only when the mites themselves, their ova or their excreta are present.
Caution: If potassium hydroxide is used for testing, it can give negative results. If the scrapings don’t contain mites or eggs, but contain only fecal matter, this will be destroyed by the potassium hydroxide; thus falsely showing no presence of scabies infection. Also, collection of scrapings from areas which are already sore can cause bleeding of superficial blood vessels.
Note: A negative laboratory report does not rule out infection of scabies. It might just mean the scrapings contained insufficient indicative material.
Causes of Scabies
Onset: This disease is caused by the female species of mites called Sarcoptes scabiei. The eggs in the skin-borrows hatch and mature into adults on the skin in about 8-10 days. The existence of eggs on the skin cause blisters. The movements and actions of the mites cause an allergic reaction and itching.
Spread of disease: Scabies is highly contagious and spreads via skin contact – especially in public places; sexually active adults or mothers having young children. Also, it can infect entire households at a time so even if some of them don’t have symptoms; they should undergo treatment as well.
Immuno-deficiency: Any deficiency of the immune system or infections like AIDS which weaken the immune system, can result in a scabies infection. This type is called Norwegian Scabies. It is more severe and needs additional treatment.
Types of Scabies
A Scabies infection has one single cause and hence cannot be truly segregated into various types. It can only be categorized as per the parts of skin affected – the hands, genitals and buttocks, breasts and nipples, etc.
Treatment of Scabies
Precaution: As it is contagious; the patient’s clothes, towels, handkerchiefs, bedcovers, etc should be soaked in hot water and separately washed.
Topical treatment: Permethrin is the most effective cure for Scabies. This is used in the topical form. The cream or lotion has to be applied after thoroughly drying the skin. No moisture or warmth should be present. Also, hydrocortisone cream or ointment is prescribed to cure the rash. Dermatologists recommend that even if some parts of the skin like fingers or feet are not affected, the cream should be applied as a preventive. The infection usually subsides in 4-5 weeks.
If permethrin does not prove effective or is not advisable, lindane lotion can be applied on the affected areas at night; which should be kept overnight and washed on waking up. In some cases, sulfur or eurax creams have to be used.
Caution: Permethrin causes side effects like stinging or burning sensation of the skin for a short while. Lindane cannot be used for scabies in pregnant women, infants, nursing mothers, children younger than 2 years of age, or those with neurological disorders. Sulfur cannot be used for scabies in pregnant women and infants less than 2 months of age.
Oral medication: Antihistamines like cetirizine or diphenhydramine are prescribed to give relief from itching. This has to be continued even after the infection appears to have reduced, as the itching sensation may continue even when the mites have died. Ivermectin is prescribed in severe cases or Norwegian Scabies to cure skin crusts.
Curative oils: Application of tea tree oil, neem (Indian plant) oil, coconut oil, olive oil, eucalyptus oil, karanja oil, lavender oil, geranium oil, peppermint oil, elecampane oil, tamanu oil, etc has proved very effective method of curing scabies infection. This method of treatment is used in cases where permethrin, lindane or sulfur would be unsafe.
Indian herbs (home remedies): These include pastes made of neem leaves or turmeric powder, which can then be applied in the affected areas. Also, tea brewed from rosemary can be applied externally on the affected areas. A mixture of clove oil and honey can be applied on the infected skin. The applications can then be wiped off with moist cloth and pat-dried after about 20 minutes.
Caution: Clove oil can cause a heat-reaction on the skin for some people.
Chinese herbs: Commercially available Chinese herbal medications containing Fructus Cnidii, Radix Arnebiae seu Lithospermi, Rhizoma Smilacis Glabrae, Cortex Dictamni Radicis, Flos Lonicerae, Herba Schizonepetae, Cortex Phellodendri, Flos Chrysanthemi Indici, etc have proved very effective in the treatment of scabies.
Homeopathic medications: In this type of treatment, sulfur is the main product used in the topical form. Mercurius viv is prescribed in the oral form.
Note: To prevent relapse, it is very important to repeat the entire course of treatment with a gap of a week.
Living with Scabies
Although scabies is not life-threatening, the constant itchiness and discomfort can be very distressful for the patient as long as the infection lasts. Also, if fungal infection sets in, the treatment takes much longer than necessary. Increase in medical costs can cause financial problems for the patient. It can sometimes reach epidemic proportions in pediatric (children) or geriatric (elderly) hospitals if not detected and controlled on time.
Prevention of Scabies
Being contagious, the initial onset of the disease may be difficult to prevent but some measures can still be undertaken to minimize re-infection and the spread of the disease. They are:
A) All family members as well as household pets, whether infected or not, should be treated simultaneously
B) The patient’s clothes, linen, etc should be washed separately
C) Physical contact, including sexual, should be avoided in the 8-week incubation period of the infection
D) Wash your hands after every application of cream or lotion and don’t share towels with others when drying your hands
E) Vacuum-clean rugs or carpets in the house
F) The bath tub should be cleaned after every use by a family member
G) While mopping floors use disinfectants
H) Keep your skin dry and cool as mites thrive on warmth and moisture.
