Causes Treatment and Prevention of Scabies 

"An eight legged mite called a Sarcoptes scabie causes scabies in humans. The mite is not visible to the naked eye. These mites burrow into the upper layer of skin where they live and thrive. It’s believed that female mites lay 2-3 eggs per day. The presence of mites in human skin results in small tunnel threadlike projections, which may appear as brown, red or grayish lines. Related symptoms includes severe itching and rash. Itch often intensifies while in bed at night. The condition is spread through prolonged skin to skin contact such as in bed, or in settings such as schools or health care facilities. Treatment options include prescription medications that uses synthetic (man made) plant extracts and natural products made from plant extracts. Prevention involves avoiding skin to skin contact, vacuuming, washing linen, washing or dry cleaning clothes and disinfecting the home or environment.  Symptoms appear up to 2 months after exposure. The condition is not spread by pets."  


Overview

The condition is caused by a mite that burrows under the outer skin layer. The mites lay eggs, increasing the size of the mite population under the skin. After a few weeks/months, the mites cause the skin to itch, and form blisters on the surface. Itch can cause eggs to get trapped under the nails, spreading the condition to other areas of the body.  Once treatment beings the problem can be resolved in 2 to  weeks. Mites are .4mm long.

The condition is not spread by pets such as cats or dogs.

Symptoms

Symptoms may appear within 4 to 6 weeks after being infested with the mite. However, it can still be transmitted to another person through close contact even though there appears to be no symptoms.  Symptoms can appear in 1 to 4 days if a person had a prior infestation.

Intense itching is the most common symptom, and it gradually becomes noticeable at night. It will get worse until the mites are eliminated. A person may experience an itchy skin rash that may appear as small red bumps, blisters or red sores. In some cases, burrow tracks or the appearance of black dots are evident. The condition usually spreads to different areas of the body, such as the face, neck, hands, palms, buttocks, nipples and breasts, genitalia, armpits, elbows, waist and scalp. It is common to experience no itching on the neck and head (the one exception is scabies in babies).

The scabies rash looks like a combiatnion of red irritated skin and scratched skin. If the area becomes infected, then pus spots will develop.  Even if you see the rash all over the body, the mites themselves are located primarily on the palms of the hands and in the spaces between the fingers. Areas where the scabies mite is burrowing will look like small lines along the skin that are grey in coor.

picture scabies skin rash
Picture Scabies Rash.  
See our
Scabies Rash Picture Collection for more pictures
Source: Naturasil Scabie Treatment Products

Diagnosis

To diagnose a rash caused by skin mites, doctors usually do a thorough examination of the patient’s skin. Doctors will look for signs of mite infestation, such as the appearance of rashes and burrows. Skin scrapings are taken from burrows for examination under a microscope in order to determine the presence of mites, eggs, or feces. In some cases, a drop of liquid or mineral oil is applied in order to scrape skin samples with the use of a scalpel.

Some doctors can also use a needle to extract a mite from the skin, and then examine the sample under the microscope to determine the type of mite. In some cases, an ink burrow test is also done. An ink burrow test involves putting washable ink on the itchy area, and after wiping it off, the burrows will absorb the ink to form a line.

Causes

What causes scabies is the parasite Sarcoptes scabiei which is attracted to the smell of human skin, human blood and body heat. It is contagious as it can be quickly passed from one person to another through close physical contact and it may spread before or after symptoms appear. An individual may be infested by scabies through their family members, from nursing homes, classrooms and babies may catch the mites from day care centers. 

Because this condition can be passed from person to person, it is important to treat the entire family or the entire group in order to eliminate the scabies and stop the infestation. Eggs from the female  usually mature within a few days, and new mites may spread through hugging, touching, sharing of clothes, sleeping on the same bed, and using other household and personal belongings of an infected person. It can also spread through sexual contact.

Animals are not a source of these types of mites and people are unlikely to contract this condition from infected animals such as dogs and cats. A specific mite only prefers one type of host so this type of mite from animals will not find the human skin as a favorable environment to multiply and thrive.  Dog scabies on humans will cause mild skin irritation and only last for a few days.  Pets cannot spread human mites.

Medical Treatment

It is important to treat this skin condition with proper medications. Generally, the condition is treated by prescription medications.  There are creams and lotions that are available through prescription that may be applied all over the body, left overnight and then thoroughly washed the following day. Treatment may take approximately 1 to 3 days.

It is also important to treat every family member in order to completely eliminate the infestation. The most common treatment for scabies is the medication  Permethrin cream 5% (Elimite and Acticin). It is considered to kill mites faster and more effectively than Crotamiton (Eurax). Crotamiton 10% is not often used or prescribed because it is not as reliable in killing mites and their eggs. Permethrin, Crotamiton and sulfur ointment 5-10% are the only prescription medications that are used to treat pregnant and breastfeeding women and children below 2 years. Natural remedies for scabies are also available.

Doctors may also prescribe Lindane 1% if the problem still persists after using other medications. However, Lindane may possess some serious side effects that it should not be used for more than one application. It should not be used by pregnant and breastfeeding women, babies, individuals who are immunocompromised, and those who weigh less than 110 pounds.

Oral medication such as Ivermectin may be prescribed if patients do not respond to lotions and creams. Antihistamines (Benadryl) may be used to relieve itching. However, it is not meant to kill scabies.

If after treatment the skin still itches, then either the first treatment did not work due to resistance to the insecticide used or the burrows and secretions left behind by the scabies mite did not heal yet. Itching can last for several weeks after treatment.

When applying a treatment it is important to treat the entire body, except the face. Ask your Doctor about any required exceptions to manufacturer directions.  For example, the packaging may say stop at the neck, when the scalp should be treated as well. Also, instructions say apply 2 treatments, when often 3 are needed on days  1, 2 and 7.

If the process has failed it is better to repeat it, as I have directed using one of the older, and to be fair less pleasant preparations, benzyl benzoate, which is still available.

In the meantime try a sedative antihistamine such as chlorpheniramine, (Piriton,) to help the itch.

Home Treatment

Mites are effectively treated with prescription medications or with over the counter home remedies  that use plant extracts such as Natruasil. This is the treatment of choice for individuals that want to avoid insecticides. 

To help eliminate the problem, it is important to wash linens, bedding and clothing in hot water that as worn up to 2 to 3 days prior to the scabies diagnosis.  Also vacuum carpets and rugs, as soon as prescription or natural treatment starts in order to kill all live mites and their eggs. 

To minimize the itching, soak a washcloth with clean and cool water and apply to irritated skin. Soothing lotions such as calamine lotion may be applied If itch persists, consider a natural supportive remedy formulated to stop scabies itch such as Scab-Ease Itch Relief.

Ask a Dermatologist
9 Doctors are Online Now.
A Question is Answered Every 12 Seconds!
Ask a Dermatologist >

References and Resources:

Center for Disease Control (2008)

McCroskey, A. & Rosh, A. (2009), Scabies Retrieved on March 7, 2010

Brochure from the British Association of Dermatologists (2013)

 




[?] Subscribe To This Site

XML RSS
follow us in feedly
Add to My Yahoo!
Add to My MSN
Subscribe with Bloglines


Please Click +1 If You Like This Site



Ask a Doctor Online
12 Doctors are Online.
A Question is Answered Every 11 Seconds!
Ask a Doctor >


Ask a Doctor
7 Dermatologists are Online Now.
A Question is Answered Every 12 Seconds!
Ask a
Dermatologist