Mites are microscopic, eight-legged parasites that can live on animals, including dogs, cats, and humans. They either burrow into the skin or into hair follicles to lay their eggs.
In this article, we look at the differences between mange in humans and animals, along with symptoms, treatment, and prevention of mite infestations in humans.
Mange in humans vs. animals
The mites that cause scabies, which can affect the fingers, are called "sarcoptes scabiei hominis".
Image credit: Fhgd, 2012
Different species of mites affect different animals — for instance, sarcoptic mites of the species Sarcoptes scabiei canis cause the mange that some dogs develop. Humans cannot catch mange from a dog or cat.
The mites that affect humans are a different subspecies called Sarcoptes scabiei hominis. These mites cause a contagious condition called scabies, which can spread quickly among people through physical contact.
Animal mites do not survive well on human skin. After contact with an affected animal, a person may notice red welts appear, similar to a mosquito bite, but this should be temporary. A person can use cortisone to reduce inflammation and itching.
However, a person can get scabies through close physical contact with a person who already has the condition. Less frequently, scabies can be spread by sharing clothing or bedding with an infected person.
Scabies is a common disease throughout the world. It is more problematic in areas that are overcrowded or have poor sanitation.
In a person who has never had contact with scabies mites before, symptoms may not appear for 2 to 6 weeks after infection. However, a person can still spread scabies to other people when they are not experiencing symptoms.
A person who has had scabies before may experience symptoms as early as 1 to 4 days after infection.
- intense itching, which can be more severe at night
- a skin rash between the fingers, which may look like small blisters
- small tracks of blisters or bumps, called burrow lines, where mites have traveled
Symptoms of mites most commonly appear in areas with skin folds, including the fingers, palms, buttocks, under the breast, and the inner knee and elbow.
Scabicide drugs must be prescribed by a doctor.
Scabies can be treated using scabicides, which are drugs that kill the mites and destroy the mite eggs. Effective scabicides are not available over-the-counter and must be prescribed by a doctor.
Common medications prescribed by the doctor include permethrin cream 5 percent (Elimite), lindane lotion, crotamiton (Eurax), or ivermectin (Stromectol).
Once prescribed, scabicide lotion should be used in the following way:
- apply the cream to clean skin
- leave it on for as long as the instructions recommend
- cover the entire body up to the neck for maximum effectiveness
- in children and infants, also apply the cream to the scalp
- after treatment, change into clean clothing
Sexual partners and people who were in close contact with the infected person should also be tested and possibly treated for scabies, as it is highly contagious. Each person should have treatment at the same time to prevent a re-infection.
For people who cannot use these medications or who do not respond to them, the doctor may prescribe other medications, such as sulfur compounded in petrolatum.
Alongside using scabicide medication, a person can take action at home to relieve itching and pain related to the skin irritation. These include:
- soaking the skin in cool water or applying a wet washcloth to the skin
- applying a soothing lotion to the skin, such as calamine lotion
- taking antihistamines
It is recommended to wash all clothes, towels, and bed clothes 3 days before treatment to avoid spreading the mites.
Some actions can be taken to prevent mites from spreading to other people, and to avoid a re-infection.
- Around 3 days before treatment, wash all clothes, towels, and bedclothes with hot water and soap, then place in a hot dryer or dry clean. Mites cannot survive for more than 3 days when they are not on a human's skin.
- Place clothes or bedding that cannot be washed in a sealed plastic bag for at least 72 hours, though the longer, the better.
Scabies is highly contagious. Symptoms of scabies can take up to 2 months to appear after the infection, though an infected person can pass the mites on to others without knowing during that time. A person who has previously had scabies may experience symptoms 1 to 4 days after the new infection.
Although contagious, scabies can be treated readily with topical creams called scabicides, which kill the mites and their eggs. After treatment, itching can persist for some weeks before going away completely.