Skin parasites in humans are killed by a combination of topical creams, oral medications, and environmental cleaning, depending on which parasite you’re dealing with. The most common culprits are scabies mites, head lice, hookworm larvae, and Demodex mites, and each one responds to different treatments. Here’s what works, how it works, and what to expect.
Scabies: Topical Creams and Oral Medication
Scabies is caused by tiny mites that burrow into the top layer of your skin, causing intense itching and a bumpy rash. The two frontline treatments are permethrin 5% cream (applied to the entire body from the neck down, left on overnight, then rinsed off) and oral ivermectin (a single pill dosed by body weight, sometimes repeated one to two weeks later). Both are prescription medications, and both are effective for most cases.
That said, permethrin resistance is a growing problem. A meta-analysis found a trend of increasing permethrin treatment failure in studies published from 2011 onward. In a 2024 Austrian clinical trial, benzyl benzoate 25% emulsion cleared scabies in 87% of patients compared to just 27% for permethrin 5% cream. An Italian study found that nearly two-thirds of patients who didn’t respond to permethrin improved with a different topical treatment, suggesting the issue was drug resistance rather than people applying the cream incorrectly. Regions with heavy permethrin use, such as parts of Australia, have reported especially high resistance rates.
If your first round of treatment doesn’t seem to work after two weeks, that doesn’t necessarily mean you did something wrong. It may mean the mites in your area have developed resistance, and your doctor may switch you to a different medication.
Sulfur Ointment: An Older Option That Still Works
Sulfur ointment at 10% concentration is one of the oldest antiparasitic treatments and remains a solid option, particularly for infants, pregnant women, and others who can’t use stronger chemicals. A retrospective study comparing 10% sulfur ointment to 5% permethrin cream found sulfur was significantly more effective at clearing scabies. Younger patients responded better to both treatments. Sulfur is applied for three consecutive nights, washed off each morning, and repeated as needed. The main downside is its strong smell and the yellowish residue it leaves on skin and clothing.
Head Lice: Choosing the Right Pediculicide
Head lice live on the scalp and feed on blood, but they don’t burrow into skin the way scabies mites do. Over-the-counter permethrin 1% cream rinse is the most widely used first-line treatment, but it only kills live lice, not eggs at every stage of development. That means you almost always need a second application 7 to 10 days later. In clinical trials, only 44% of children treated with permethrin were lice-free after 14 days.
Spinosad 0.9% topical suspension, a prescription product approved by the FDA in 2011, performs considerably better. It kills both lice and eggs at all stages, which means most people don’t need to comb out nits afterward. In the same trial, 85% of children treated with spinosad were lice-free at 14 days, and 75% needed only a single application. Malathion lotion is typically reserved for cases that resist permethrin.
One older medication, lindane, carries serious risks and is rarely used today. It can cause seizures, nervous system overstimulation, and in rare cases death, even after a single application used as directed. Infants, children, elderly patients, and people weighing less than 110 pounds (50 kg) face the highest risk of severe neurological side effects.
Hookworm Larvae Under the Skin
Cutaneous larva migrans is a hookworm infection you can pick up by walking barefoot on contaminated sand or soil, especially in tropical areas. The larvae can’t complete their life cycle in humans, so they wander through the upper layers of your skin, leaving red, snaking, intensely itchy trails. An oral antiparasitic taken for three consecutive days clears the infection. Some evidence suggests a single oral dose may be enough, though a short course is more commonly prescribed. The tracks and itching usually resolve within a week or two of treatment.
Demodex Mites on the Face and Eyelids
Demodex mites are microscopic parasites that live in hair follicles, particularly on the face and eyelashes. Most people carry small numbers without symptoms, but an overgrowth can cause redness, flaking, and a condition called Demodex blepharitis, where the eyelids become inflamed, itchy, and crusty.
In 2023, the FDA approved the first treatment specifically targeting Demodex blepharitis: a prescription eye drop applied twice daily for six weeks. The active ingredient belongs to a class of compounds that paralyze the mites’ nervous systems, preventing them from feeding, which leads to starvation and death. For Demodex on facial skin (as opposed to the eyelids), tea tree oil-based products and other topical treatments are sometimes used, though options are more limited.
Tea Tree Oil: What the Lab Data Shows
Tea tree oil has genuine antiparasitic properties, but the details matter. In lab studies, solutions of 5% to 10% tea tree oil killed scabies mites within 10 to 60 minutes. A 15% tea tree oil lotion achieved 100% mite death within three hours. One clinical trial in children with scabies compared 5% tea tree oil cream, a combination of 5% tea tree oil with 5% permethrin, and permethrin alone. Another study used 5% tea tree oil mixed into benzyl benzoate lotion alongside oral ivermectin for crusted scabies, a severe form of the disease.
The catch is that killing mites in a lab dish is easier than killing them in living skin, where they’re burrowed beneath the surface. Tea tree oil shows promise as a complementary treatment, but it hasn’t replaced prescription medications in clinical guidelines. If you want to try it, look for products with at least 5% concentration, and don’t rely on it as your only treatment for a confirmed infestation.
Killing Parasites in Your Environment
Treating your skin is only half the job. Scabies mites can survive off the body for up to 72 hours, and lice can live on clothing and bedding for a similar window. If you don’t clean your environment, you risk reinfesting yourself.
The CDC recommends washing all bedding, clothing, and towels in hot water and drying them on the hottest dryer setting. Temperatures above 122°F (50°C) sustained for 10 minutes kill both mites and their eggs. For items that can’t go in the washer, either dry-clean them or seal them in a plastic bag for at least 72 hours, and up to one week to be safe. Vacuuming mattresses, upholstered furniture, and carpets is also worthwhile, though surface cleaning alone won’t eliminate an infestation without simultaneously treating everyone in the household.
Getting the Right Diagnosis
Different skin parasites cause symptoms that can look surprisingly similar: itching, redness, bumps, and irritation. Treatment only works if you’re targeting the right parasite. Doctors diagnose scabies using skin scrapings (examining a sample under a microscope for mites or eggs) or dermoscopy (using a handheld magnifier to look for mite burrows directly on the skin). Dermoscopy picks up about 83% of scabies cases, but it also produces a fair number of false positives, with a specificity of only 46%. Skin scraping is more definitive when it’s positive, but mites can be hard to find, especially in early or mild infections.
For lice, diagnosis is usually straightforward: live lice or nits (eggs) are visible on the hair shaft near the scalp. Hookworm tracks have a distinctive serpentine pattern that’s hard to mistake for anything else. If you’re itching and you’re not sure why, getting a proper diagnosis before starting treatment saves you from cycling through products that won’t help.