The vast amount of internet discussion notwithstanding, Dr. Taylor suggests patients rid themselves of scabies with conventional scabicides, not unproven natural approaches. If you Google “scabies” and “natural remedies,” you will get hundreds of hits. There are many internet sites devoted to this pesky problem. Among the recommendations are applying tea tree oil, eating a diet of only fresh citrus fruit, and even ingesting raw egg yolks. Family physicians, pediatricians and dermatologists evaluate and treat a lot of patients for scabies, many of whom do not like the idea of using strong chemical insecticides on their own or their children’s skin. In addition to concerns about toxicity, resistance of the scabies mite to conventional topical and oral therapies is increasing.1 Let’s quickly review what scabies is, the natural remedies that your patients may be trying, and whether anything natural is likely to kill those mites.
Scabies and its Symptoms2
Scabies is a parasitic infestation in which tiny Sarcoptes scabiei mites burrow under the skin and cause intense allergic itching. The itching of scabies results primarily from the body’s allergic reaction to the mites, their eggs and their feces. Intense itching, which is classically worse at night, is the main and most bothersome symptom. Aside from the itching, symptoms may include red or urticarial papules on the skin. These lesions can be found on the fingers, wrists, elbows, waist, buttocks and genital area. The mites can also burrow under fingernails or around the skin near watchbands or rings. Breaks in the skin from vigorous scratching can lead to secondary Staphylococcal and Streptococcal bacterial infections. It is important to remember that people infected with scabies usually have no symptoms during the first 2 to 6 weeks they are infested; however, they can still spread scabies during this time.2
Sarcoptes scabiei var. hominis, the human itch mite, is in the arthropod class Arachnida, subclass Acari, family Sarcoptidae. Sarcoptes scabies is an eight-legged mite. Females burrow into the stratum corneum, creating a tunnel in which they deposit their eggs. Female mites live for 4 to 6 weeks and produce two to three eggs per day, which are deposited in the burrowed tunnel. Larvae hatch 3 to 4 days after the eggs have been laid, and adult mites develop 10 to 14 days later. Under the most favorable of conditions, about 10% of the eggs eventually give rise to adult mites. The new adult mites move closer to the skin’s surface, from which they can spread to other areas of the skin or to other people.2 Close physical contact and, less often, sharing clothing or bedding with an infected person can spread the mites. The mites can live for up to a month on the human body, but can’t survive for more than 48 to 72 hours elsewhere. Also, humans cannot get scabies from pets. Dogs and cats attract other types of mites that don’t survive on the human body. Scabies occurs worldwide and has no predilection for certain races or social classes. Scabies can be a significant public health problem, as it can be spread in environments with numerous people in an enclosed setting such as hospitals, rehabilitation centers, childcare facilities, nursing homes and correctional institutions.
Scabies is often diagnosed by a history of intense itching that is worse at night in addition to an erythematous papular eruption with excoriations. Characteristic burrows may or may not be present. Scrapings may be taken of a burrow to determine the presence of mites, mite eggs or mite feces on microscopic examination. However, a person can still be infested, even if mites, eggs or fecal matter cannot be found; fewer then 10 to 15 mites may be present on an infested person who is otherwise healthy.
Conventional Treatment Options2-6
Conventional medical treatment for scabies involves various types of scabicides. All of these are by prescription only, as there are no over-the-counter preparations approved to treat scabies. Primarily used are permethrin (Elimite, Acticin), lindane and malathion (Ovide), with permethrin being the drug of choice. By itself crotamiton (Eurax) is not as effective as the others, but some physicians prescribe it in addition to one of these preparations. Most are considered to be of low toxicity. However, lindane has fallen out of favor because of numerous reports of neurotoxic symptoms such as skin numbness, restlessness, anxiety, tremor and convulsions. These scabicidal creams or lotions are applied over the entire body, from the neck down, where they are left on the skin for at least 8 to 12 hours, then washed off. These medications effectively kill the mites, but itching may linger for several weeks as the immune system still responds to the eggs, waste and dead mites themselves. Sometimes oral medications are prescribed for people with compromised immune systems or resistant rashes not responding to prescription topicals; ivermectin is a common and effective choice. The safety of ivermectin in children weighing less than 15 kg and in pregnant women has not been established. Oral or topical antihistamines are often recommended to relieve intense itching. In addition to the infested person, treatment also is recommended for household members and sexual contacts, particularly those who have had prolonged direct skin-to-skin contact with the infested person. Both sexual partners and close personal contacts who have had direct prolonged skin-to-skin contact with an infested person within the preceding month should be examined and treated. All persons should be treated at the same time to prevent reinfestation.
Natural Remedies for Scabies
There is less scientific information about the anti-scabietic activity of natural treatments and their clinical and pharmacologic characteristics compared with conventional treatments, which means more controversy and uncertainty about their use. Among the natural compounds discussed below, tea tree oil is perhaps the most studied preparation and shows the most promise as an effective agent against the scabies mite. Tea tree oil (Melaleuca alternifolia): 7,8 Tea tree oil topical preparations are readily available in health food stores. The principal antimicrobial in a wide range of pharmaceuticals sold in Australia, with the main active component being oxygenated terpenoids, tea tree oil is highly effective in vitro, demonstrating rapid killing times of the mites as compared to permethrin and ivermectin. Human studies, however, are lacking. Neem (Azadirachta indica) and Turmeric (Curcuma longa):9 The neem tree belongs to the mahogany family and is found in many of the Asian countries, especially India. Turmeric is a rhizomatous herbaceous perennial plant of the ginger family, Zingiberaceae. It is native to tropical South Asia. In the Ayurvedha and Sidha system of medicine (Indian system of medicine) Azadirachta indica ADR (‘Neem’) and Curcuma longa (‘Turmeric’) have been used for healing of scabies and chronic ulcers. There is one study using a paste of each of these natural products on 814 individuals with scabies, with 97% of people showing cure within 15 days of treatment. Bush tea (Lippia multiflora):10 This is a plant native to Africa, commonly known as ‘Tea of Gambia,’ and is widely used in Africa for many medical problems. In a clinical trial in Nigeria involving 268 male prison inmates, it was compared to OTC benzyl benzoate, a treatment rarely used by physicians due to its low efficacy for killing mites compared to permethrin. The trial showed a higher cure rate using essential oil from the leaves of the bush tree than the benzyl benzoate (100% versus 87%, respectively).
What to Tell your Patients
Among the natural treatments above, tea tree oil shows the most promise as an effective agent against the scabies mite; however, it has not been studied in humans and is thus not recommended as an effective treatment at this point in time. Therefore, I recommend patients first seek conventional treatment and to take these measures to prevent reinfestation and the spread of mites to other people. • Use hot (60oC/140oF) soapy water to wash all clothing, towels and bedding that were used at least 2 days before treatment. Machine-dry with the highest heat. Dry-clean items that can’t be washed at home. • Nonwashable articles should be isolated for 2 to 4 weeks in sealed plastic bags with the expectation that the mites will die within a few days. Mites cannot survive off human skin for more than 2 or 3 days. This bag should be put somewhere such as the garage or outside. • Vacuum the entire house thoroughly and throw away the vacuum cleaner bag to prevent any mites from escaping into the house.
Dr. Taylor, a resident in the Department of Dermatology at Wake Forest University Baptist Medical Center in Winston-Salem, NC, is board-certified in Family Medicine, which she practices in Winston-Salem, NC. Disclosure: Dr. Taylor has no conflict of interest with any materials presented in this article.