Scabies is a type of skin infection caused by the sarcoptes scabiei mite, characterized by skin itching. Also termed “sarcoptic mange”, the term scabies is actually derived from the Latin word for “scratch”, scabere. The tiny mites burrow within the skin, causing an allergic reaction which in turn leads to a rash and acute itching. Worldwide, there are an estimated 300 million people infected with scabies at any one time.
History of Scabies
An ancient disease, scabies is thought to be over 2,000 years old. Historians speculate that references to scabies are found in the Bible as well as the writings of Aristotle.
The mite affects humans regardless of age, gender, socioeconomic status, or race.
Personal hygiene is often not considered a factor in scabies, although washing contaminated items with hot soap and water can often kill the mites.
Scabies occurs when female mites burrow into the human skin to lay eggs, creating tunnels underneath the surface. The mites feed on human skin and deposit their eggs waste products, which further exacerbate itching.
The eggs, over the course of three to four days, hatch into larvae, which further infect the skin and live on the human host for three to four weeks inside the skin. The scabies feed on the blood of the host to survive, and further burrowing in the skin. The allergic reaction humans have to the mites’ salive, waste, and eggs cause the deep seated and persistent trademark itching of scabies.
The first and most obvious sign of scabies is localized itching. Mites may or not be visible, but usually will leave small red bumps and tiny zig zag pathways where they have burrowed into the skin. These bumps may look like tiny pustles or blisters or resemble small pimples on the skin. Scabies tends to affect areas of skin folds, such as the inside of elbows, between fingers, behind knees, wrists, and other areas.
In patients where the immune system is weakened, scabies can develop to form crusted scabies, an advanced form of the disease where crusted patches of scabs form as a result of infestation. Thickened patches of skin containing hundreds of mites can form in crusted scabies.
Typically, the face and scalp are not affected by scabies. Scabies may remain localized in one area or gradually spread over the surface of the skin.
Scabies is transferred via skin to skin contact from one human being to another. There have been cases where humans contract scabies from their pets, such as an infected dog or cat, but such occurrences are rare. Highly contagious, scabies mites can live in infected bedding, furniture, mattresses, clothing, keyboards, towels, and literally almost any surface where an infected human’s skin may have rubbed off. Additionally, scabies can survive without a host for up to three days. Once they have infected a human host, the parasitic mites can live anywhere from three to four weeks.
The most common way of contracting scabies is from prolonged physical contact with an infected person. While patients have been known to get scabies from infected bedding or clothing, this is less common. Prolonged physical contact usually means skin to skin contact with an infected person which lasts longer than the average handshake.
High Risk Areas
Scabies often becomes a problem in areas where people exist in close quarters, such as nursing homes, summer camps, or schools. In these environments, one infected individual can spread the disease to anyone he or she comes in close contact with.
The type of scabies that affects humans is different from the mite that infects dogs and cats. Humans typically cannot be infected by the same type of scabies mite that affect pets.
Scabies can exhibit clinical symptoms and external signs from four to six weeks following the initial infestation for patients who have not previously contracted the disease. In cases where patients have previously contracted scabies, symptoms can develop in as quickly as two to four days.
Once patients have exhibited symptoms, several methods can be used to diagnose the symptoms as scabies. Ink from a pen or topical tetracycline ointment can both be rubbed onto the surface of the skin, then wiped off with an alcohol pad. A special light is then shown on the skin; if the characteristic Z pattern appears under the light, the person has scabies.
Another method of diagnosis is to do a skin scraping and examine the specimen under a microscope for presence of mites or their waste. Detecting the presence of mites can often be very elusive, and doctors may have to do numerous skin scrapings in order to effectively rule out or confirm the disease. The skin scrapings must often penetrate several layers of skin in order to correctly test for the presence of mites.
Doctors have been known to order treatment for scabies even if microscopy and other detection techniques do not completely verify the infection. Due to the difficulty of detecting mites under a microscope and sometimes unconfirmed external presence, patients who exhibit the majority of symptoms for scabies are best served undergoing treatment as a preventative measure even if skin scraping or skin tests do not precisely confirm presence of the mite.
Weak Immune Systems
In patients with compromised immune systems such as HIV, AIDS, or auto immune deficiency, healthcare providers should be alerted immediately to the possibility of scabies. Secondary infections can occur as complications in these patients who contract scabies, as well as increased likelihood of acute infection.
It is highly recommended that patients visit a doctor fordiagnosis and recommendations of treatment options for scabies.
While some infestations may resolve on their own, left untreated scabies can escalate into a highly unpleasant problem. Increased itching, formation of bloody scabs, and patches of scaly skin may accompany an advanced infestation. In such instances, medical treatment is the most efficient and best option. Scabies can also become resistant to medications over time, though this usually only occurs in repeat infections.
Once an infection is confirmed, the patient’s nails should be cut to prevent scabies from hiding under the fingernails or toenails.
Sulfur soap in concentrations of 6% to 10% is a long standing treatment to combat scabies. Patients should wash thoroughly with sulfur soap at least once daily for four days in order to effectively treat the skin. Bedding, clothing, and any other items should be washed in extremely hot water and soap to prevent recontamination.
Along with sulfur soap, Neem Oil is another effective homeopathic treatment for scabies. Neem Oil is known to have anti fungal and antibacterial properties, which can help treat or soothe the skin of patients infected with scabies.
Tea Tree Oil and Elimite
Tea Tree Oil has been used but with only moderate to little success. For this reason, prescription medications are often warranted for treatment.
One of the most commonly prescribed topical treatments for scabies is Elimite, a cream that must be applied to all areas of the skin (including under the fingernails and toenails) to effectively penetrate the epidermis. Elimite is topically applied all over the infected individual’s body, taking care to cover all surfaces of the skin. After 10 to 14 hours, the Elimite is washed off of the skin in the shower with hot water and soap. A follow up treatment is usually required one to two weeks after the initial treatment.
Permethrin, Oral Medications, & Antihistamines
Permethrin is another popular topically applied medication for the treatment of scabies. The ointment is applied at night and washed off after eight to fourteen hours.
A newer treatment for scabies is an oral medication Ivermectin, taken twice: once at onset, and then another dose two weeks later to completely eradicate the infection. While Ivermectin has some mild side effects, these disappear after treatment and are typically a minimal trade off compared to the uncomfortable constant itching of scabies. Ivermectin is sold as Stromecol in brand name, and is typically given as two 3mg doses two weeks apart.
Antihistamines may also be prescribed to combat the itchiness that often accompanies scabies outbreaks.
Sterilization of Household Items During and After Treatment
All items the infected person has touched- bedding, clothing, towels, etc – should immediately be washed in very hot water to kill remaining mites. A dryer should also be used on a high heat setting to sterilize washed items. Mattresses, carpets, rugs, toys, and any other items that the infected person has touched should be thoroughly disinfected and washed.
Carpets and floors should be steam cleaned whenever possible. Tile, hardwood, kitchen, and bathroom floors should be washed with hot soapy water and bleach. This regimen of household disinfecting should be performed on a daily basis until the scabies outbreak has been confirmed as cured by a healthcare professional, and on a routine basis for several weeks after to prevent re-infection.
Treatment of Family Members
Due to the highly contagious nature of scabies especially in close quarters, doctors frequently recommend treating the entire family for scabies even if only one member has contracted it. Given the propensity of the mite to spread and populate bedding, furniture, clothing, and other areas, it is highly likely that if one member of a family has scabies, other members either already have it or will have it shortly. Therefore, treating all family members for scabies at the same time is an effective method at preventing continual re-infection.
Care must be taken to ensure that once all family members are treated, scabies does not return and continue to re-infect members of the family. This requires a diligent household cleaning routine during and after treatment as the entire house must be disinfected in order to eradicate the outbreak.
Treatment for scabies is relatively inexpensive compared to other skin ailments. A 60ml tube of Elimite retails at around $35; sulfur soaps are much less, at an estimate $10 a bar. An 8oz bottle of Neem Oil has a comparable cost to sulfur soap.
Ivermectin (brand name Stromectol) is typically available in 3mg tablets. Costs for Stromectol are considerably higher (around $110 for treatment without insurance),
There is no vaccine against scabies. Therefore, the best way to prevent scabies is to avoid prolonged contact, or any contact, with people infected with scabies. If scabies contact is suspected, any bedding, clothing, towels, or items the infected person may have touched should be immediately washed in very hot water and soap.
Adding a small amount of borax to laundry can also be helpful. Rugs and floors should be steam cleaned and vacuumed.
Permethrin sprays are often used to treat items or areas that cannot be laundered. A synthetic chemical and pesticide, care should be taken when using Permethrin around infants and pets. The EPA has also categorized Permethrin as a carcinogen in extremely strong concentrations. For household use, however, Permethrin sprays can kill scabies mites, dust miles, fleas, termites, and ticks.
Borax powder is natural remedy than can be sprinkled on carpets, floors, and other areas of the house to prevent and kill mites. While natural, boric acid can still irritate the skin in some individuals and animals, so caution should be used when applying.