A Scratch for Every Itch: Compounded and Oral Treatment Options for Scabies
Last summer I adopted a puppy that I thought simply had a bad case of fleas. She scratched herself day and night, and had the classic baldness pattern that comes from the chronic itchiness of fleas. But after several flea treatments, her problem worsened. I had a horrible realization: my dog didn’t have fleas–she had sarcoptic mange, AKA canine scabies. Within a couple of days, I got it too and broke out in hives from head to toe.
Fortunately, canine scabies is not the same as human scabies. It can’t survive in the environment or on the human body for more than a few days. In reading about treatments for humans afflicted with canine scabies, I came across a number of articles and forum posts about human scabies. As uncomfortable as the dog version was, my understanding is having the human version is far worse.
What Is Scabies?
Scabies is a parasitic infestation of the skin caused by the mite Sarcoptes scabiei var. hominis, a microscopic arachnid. The female mite burrows under the upper layer of the host’s skin and lays eggs that hatch and release larvae so the cycle can keep repeating itself. The presence of the mites causes an allergic-type reaction that is actually a sensitivity to the mites’ proteins and feces.
The mites are transmitted from one person to another via skin-to-skin contact or less frequently, via fomites, such as bedding and clothes. Scabies is more easily spread in certain environments, such as prisons and nursing homes.
How Is Scabies Diagnosed?
While skin scrapings can provide a definitive diagnosis of scabies, there may only be 10-15 adult mites on a human host at any point in time, so finding them can be difficult. Their burrowing under the skin can leave tunnels which are considered indicative of the parasite, as is the itchy rash that develops about 2-6 weeks after exposure. The itching can be so intense that victims of scabies often develop staph infections from scratching the skin raw. The rash tends to form in certain areas of the body: between the fingers, on the palm side of the wrists, around the the waist and bra line, in the crooks of the knees and elbows, around the armpits, and around the male genitalia.
What Are the Treatment Options for Scabies?
The most common treatment for scabies is a 5% permethrin cream that must be applied after showering from the neck down in adults and over the entire body in infants. This treatment is considered safe for infants over two months of age, as well as for pregnant and nursing women. The permethrin cream kills the mites by disabling their nervous system, and it also kills their eggs. For complete eradication, it must be reapplied one week later.
There are other, less frequently prescribed treatments for scabies:
- 25% benzoate lotion
- 10% sulfur ointment (sometimes used in babies under 2 months)
- 10% crotamiton cream
- 1% lindane lotion
Any of these topical treatments can be easily obtained from a compounding pharmaceutical provider, like PNA. Oral ivermectin may be prescribed for patients with altered immune systems or for cases that fail to respond to any of the above treatments.
In addition to topical medications to kill the mites, antibiotics may need to be prescribed for skin infections secondary to the parasitic infestation. Oral or topical diphenhydramine or hydrocortisone cream should help quell the itching.
How Can Pharmacists and Health Care Providers Help Patients with Scabies?
Patients need to be advised that their prescription medication alone is not sufficient to rid themselves of the scabies mite. Simultaneously with pharmaceutical treatment, bedding and clothing should be washed in hot water and dried on high heat. The home should be completely vacuumed and the vacuum bag placed in a plastic bag and disposed of outside. Borax, a known miticide, can be sprinkled on carpets and left to sit before vacuuming and used to mop floors.
Fabric surfaces in the home should receive particular attention, including sofa cushions and pillows, and surfaces that can’t be cleaned can be placed in plastic bags for at least three days. Soft toys and stuffed animals should also be bagged. The family car is an often overlooked environment for scabies. The floor should be vacuumed, and the steering wheel and seat belts wiped down with a chlorine bleach solution.
There is an over-reliance on home and over-the-counter remedies to treat scabies (bleach baths, 1% permethrin products for lice, etc.). Patients should be cautioned that these treatments are not effective, and in some cases even harmful. While there is documentation of resistance to both permethrin and ivermectin, in many cases failure to respond to treatment can be due to:
- improper use of the prescribed treatment
- failure to repeat treatment at the appropriate interval
- poor environmental control allowing reinfection
- repeat contact with a scabies source
- patient infested with a non-scabies mite (bird mite, rodent mite, etc.)
Eradication of scabies is much like treating fleas in canines: the proper treatment must be used in the manner prescribed; the environment must also be addressed; repeat contact with a parasite source must be avoided; and all aspects of the treatment regimen must be performed at the same time.
For information about compounding topical medications contact Pharmaceutica North America. We are your resource for high-quality bulk compounding materials, and we can advise you about treatment regimens and effective carrying agents.