Scabies is a skin disease caused by the infestation of the mite, Sarcoptes scabiei. These organisms are too small to be seen with naked eye. Infestation by this mite is common worldwide. People of all age groups may be affected by this skin condition and is very common in areas that are congested, including nursing homes and hospitals.
Scabies affects people of all classes and ethnicities. It is an ancient afflation. From last 2500 years it has infected humans. Scabies is considered as water related disease as per WHO. However, the tick that spread scabies does not transmit the disease through water nor needs water for any part of its life cycle. The tiny mites burrow and lay eggs inside the skin of humans hence scabies is an infestation and not an infection. As the mites lay eggs it leads to symptoms itching and severe rashes.
Morphology and life cycle of mite
It is an eight- legged arthropod with round body. Females are less than 0.5mm in length. Females are larger than males. Mites are barely visible to human eye. Adult mites burrow into the upper layer of the skin and the eggs laid by the female hatch after three to four days into larvae. These larvae dig new burrows close to the skin surface. In four days these larvae mature into adult mites. These adult mites may either stay in the same host or be transmitted to a new host.
This disease spreads by close contact with the infected person. Sharing of personal things including towels and bed sheets also results in the spread of the mite. It is possible to spread the disease to other people even before the symptoms of the condition appear on the body. The spread is common in college dormitories, hospitals and nursing homes. Spread of this disease from pet animals is not seen.
It is not possible to catch scabies from a cat or a dog since the same type of mite that causes scabies in humans does not cause scabies in animals. The type of scabies that infests dogs or cat is “mange”. These mites if spread to humans may cause minor itching and redness but they die out on their own since they cannot survive or reproduce on human skin. If a mange mite’s spreads to humans, then treatment is not required but dogs and cats need to be treated because scabies in them caused by mange causes loss of fur and itchy skin.In many cases, it may affect most of the family members at the same time.
Scabies can also get transmitted from parent to the child particularly from mother to the infant. Without human contact more than 72 hours the mite cannot survive, though it is still possible for the scabies to spread through infested furniture or bedding. Once the mite comes in contact with human skin they can live up to two months. In colder conditions and higher humidity these mites survive longer. Usually three to six weeks after infestation symptoms begin to appear.
Often scabies looks like small red pimple-like bumps on the skin. They can be crusty and accompanied by ‘burrows. Sometimes from these bumps thin gray, brown or red lines may radiate. These might look like scratch marks.
Rashes, blisters, and sores are the most common symptoms of scabies. Rashes are mostly seen in between the fingers and are also apparent on head, face, and palms. Itching is also common, which increases in the night. The affected areas on the skin may have thin thread like lines. Rashes and sores start appearing on the skin after several weeks of mite infestation, especially if you are having it for the first time. If the skin has been exposed to mites earlier, symptoms will appear soon enough.
The activities and secretions of the mites cause allergic reaction. The signs include a vesicular rash, intense itching of infected areas, and burrows in the skin which are visible. Intense itching can cause bleeding and scab formation. Scratching can cause secondary bacterial infection. Intense itching can cause disturbed sleep. The mites prefer the body areas like the wrists, elbows, armpits, skin between the fingers and toes, around the nails, skin covered by clothing such as belt line, nipples, groin, and buttocks. The scabies rash in infants and young children may appear on their head, neck, face, palms and soles. Individuals whose immune system is compromised may experience Norwegian scabies. There is extensive scaling and crusting. Often the itching caused by scabies worsens at night and it starts as a minor symptom and progresses to a point where the person is unable to sleep.
The appearance of track like- burrows in the skin is a hallmark of scabies. The female mites tunnel under the skin surface. Each female lays 10 to 25 eggs under the skin surface.
Diagnosis of scabies is based on the symptoms on the skin. The chances of getting this infestation is high if any of the family member had or if you had close contact with people with mite infestation. Observing the affected skin scrapings under the microscope reveals the presence of mites. Those who have symptoms of this skin condition should ideally meet the doctor for correct diagnosis.
Special prescriptions are given by the doctor for treating this condition. In severe cases of scabies, pills are prescribed. People who have had close contact with you like children also should have treatment as the mites spreads rapidly from one person to another. Those who have the infestation should clean their personal belongings carefully to avoid the spread of the disease.
Even after treatment, the rashes and itching may last for few more weeks. This time period is used by the body to get over the allergic reaction. If the rashes continue even after several weeks of treatment, one more round of treatment may be needed.
Facts About Scabies:
- Scabies is not really an infection, but rather a mite infestation in the body. Tiny mites attack the body, and lay their eggs inside the skin surface. The skin objects to this external infestation which results in reactions like severe itching and angry rashes all over the affected areas.
- The first infestation with the mites, takes time to show up in a patient. A patient may take about four to six weeks to react when the scabies infestation sets in for the first time.
- Severe itching, pimples like rashes, blisters and sores are some of the most common signs and symptoms of scabies.
- At the onset, a scabies disease is often mistaken as another skin infection as the rash looks very much like the other skin infections.
- In case of children and older adults, the scabies disease could cause very severe itching and discomfort around the skin.
- the mites causing scabies can live anywhere on the skin, however they are largely found between fingers; folds in the body like the elbow, knees and thigh; around the breasts especially under the breasts; around the navel region.
- Scabies mite can be very difficult to see for the naked eyes. Usually the mite is identified under the microscope by scrapping the skin.
- Direct skin contact with the infected causes the scabies infection to spread easily from one person to another.
- Pets can get the scabies infection as well, however this occurs with another type of scabies mite and not the same one which affects the humans. In fact the scabies mites that infect the pets cannot survive on the human skin and if they get transferred do not live long.
- Daycare going children are at high risk of catching the scabies infection. In case a kid has been detected with the infection, then the caregivers and the other students in the day care would also need to be given an appropriate treatment for the infection.
- Crusted infestation is a type of the scabies infection wherein a person gets infested with over 10,000 mites at a single time. This form of the scabies infection can become highly contagious and can easily spread from one person to another.
Is Scabies a Contagious Disease?
Scabies is a highly contagious disease that can easily spread from one person to another in any one or more ways:
- Direct skin contact with the infected for a long time like holding hands
- Having a sexual contact with the infected person
- Direct sharing of personal belongs of the person infected with the scabies infection
Since the scabies infection is a highly transmutable disease that spreads through direct physical contact, it puts the direct family members living with the infected person, friends and sexual partners at a high risk of catching the infection. Schools, hospitals, sports locker rooms are some of the most common breeding grounds of this infectious disease. Sexually active inmates, prison inmates, people living in crowded conditions, people in child care facilities and people in institutional care are at a higher risk of getting scabies.
Diagnosing the Scabies Infection
Sometimes scabies may be mistaken for other condition of the skin since the rashes look the same. The images of acne, mosquito bite and scabies are almost the same. It may look like eczema or tinea including ringworm, athlete’s foot and jock itch. But the relentless, severe itching in scabies sets it apart from others. For correct diagnosis and treatment, it is important to see a doctor.
Diagnosing the scabies infection is not very difficult for the doctor based on the physical checkup and symptoms of the patient. The doctor performs a physical examination to diagnose scabies. The doctor conducts a careful examination of the affected area of the skin. In certain cases, the doctor may remove a mite from the affected area of the skin with a needle. If the mite cant be found then a small portion of the skin is scrapped to obtain a sample for microscopic testing.
Other methods are:
Dermoscopy- in this a handheld dermoscope is used. It allows closer visual examination of the skin. This is to look for mites.
Adhesive tape tests- a strong adhesive tape is applied to the skin lesions. It is then pulled off. Then it is observed under the microscope to look for mites.
To treat the scabies infection, the objective is to primarily get rid of the infestation that is the root cause of the infection. If the infestation is not treated, then there are always chances of a relapse of the scabies infection in the patients. There are various forms of medications including ointments, creams and lotions which are topical treatments meant for instant relief for the patient suffering from the scabies infection. There are also several oral medicines that may be prescribed to the patient in lieu of the scabies treatment.
The doctor might suggest you to apply the topical creams and lotions prescribed before bedtime, as this is the time when the mites get active, aggravating the infection. Apply the medication liberally neck down all over your body so that the mites do not affect the presently unaffected parts of your body. Most of the medications prescribed for scabies are safe for the skin and can be easily washed off the next morning. It is important that you complete your treatment course and follow the doctor’s instructions to the tee. You may be required to continue the treatment for at least 7 days or as long as the infection lasts, whatever the doctor finds best.
Creams and lotions
Topical cream such as permethrin (Elimite) is the first line treatment for scabies. It is applied directly to the skin. Usually after one to two weeks second application of this cream is recommended. Other topical creams include crotamiton (Crotan, Eurax) cream or lotion, lindane (since it has high risk of seizures hence not used as a first line treatment), sulfur ointment and benzyl benzoate.
Oral ivermectin particularly in cases where scabies covers a larger area of the body and is crusted. The dose recommended by The Centers for Disease Control is 200 mcg/kg as a single dose. It is to be repeated in two weeks. It does not cause any related skin problems and is easy to use. However, there may be some unwanted side effects hence it is not the first choice of treatment.
Some over-the counter antihistamines such as diphenhydramine (Benadryl) is available which gives relief from itching and allow sleeping.
The doctor might also recommend some medications that are effective in treating the symptoms associated with the scabies infection. Again, most of these medicines are safe and largely help in giving the patient relief from the extremely bothersome symptoms. However, if you think some symptoms are getting worse, speak to your doctor immediately without any delay. In case you don't find much relief from your treatment or your symptoms exist even after four weeks of taking the treatment, consult your doctor, as he may recommend some alterations in the medications.
Usually the scabies medications kill the mites and eggs quickly. The patient can return to school or work 24 hours after the treatment has started. However, if the itching continues for more than four weeks then see a doctor right away.
Natural Remedies for Scabies
Although immediate treatment should be administered to a patient suffering from the scabies disease, there are several home remedies that can help in control the infestation from spreading and treat the affected area of the skin safely without any side effects.
- Cayenne Pepper: Cayenne pepper contains capsaicin, which is a natural pain reducing chemical. This compound also helps in relieving symptoms of itching and burning on the skin thereby helping in reducing the impact of the infection.
- Tea Tree Oil: Tea tree oil is a potent natural remedy that is beneficial in treating a number of ailments of the skin. Tea tree oil contains certain anti microbial properties, which safeguard the skin from any secondary infection resulting from the scabies. Do not apply tea tree oil directly to the skin as it can cause serious burning, instead dilute it in your bath.
- Clove oil: Clove oil has anti bacterial and anti inflammatory properties, besides being an analgesic that helps in relieving the itching sensation caused by the scabies infestation.
Scabies mites do not survive without human contact more than 72 hours. Still it is better to machine wash bed linens and clothes in hot water and dry on high heat. These items can also be dry cleaned. Furniture’s and carpets need not be cleaned.
It should be ensured that all those who are in contact with the infested person should be treated
Clean off any mites or eggs by keeping your fingernails and toenails well trimmed.
Vacuum carpets furniture’s and interiors of the car. Discard the vacuum pump bags.
Avoid scratching lesions or bumps caused due to scabies
Keep sores open and clean
It may take few days for the itching and other symptoms to subside once the treatment starts. If it doesn’t then see a doctor.
It is another name of crusted scabies. Norwegian scabies usually tends to occur in patients whose immune system is compromised such as HIV/AIDS or cancer or elderly patients or a person with Downs’s syndrome. Large numbers of scabies mites are present on a person with crusted scabies and they are very contagious. Scalp, hands and feet are commonly affected but it can affect any area of the body. Scales become warty. Crusts and fissures appear on the scales. Lesions may smell bad. Nails may become thick and discolored. Some may experience symptoms of itching.
It is difficult to resist scratching in scabies due to the intense itch. Frequently if the sores are itched then it can open the sores which will make it prone to infection. The most common complication of scabies is bacterial skin infection such as impetigo. The symptoms of this include honey-colored oozing blisters. This bacterial skin infection is usually treated with antibiotics.