Skin parasites are small or even microscopic bugs that burrow into the skin and cause itching and other uncomfortable symptoms. Signs of infection are usually visible on the skin's surface as red lines or raised bumps.
Types of Parasites
In order for parasites to live and thrive, they must have a host. Parasites depend on their hosts for food and protection. Animals and humans are both hosts to parasitic life. Most parasites prefer burrowing into hair or furry areas, but this is not necessary for all parasites.
- Obligate - Obligate parasites live in the host's skin for its entire life cycle. A type of obligate parasite called "facultative" can live for a life cycle without necessarily sickening the host.
- Accidental - Accidental parasites use hosts for part of their life cycle but cannot exist their entire lives in the host's skin.
Common Skin Parasites
There are several types of parasites which commonly infest human skin - some more prevalent than others.
- The CDC also states that body lice are not common to those who have access to regular bathing and laundering of bedding and clothing, but can spread rapidly in crowded living conditions where standard hygiene is difficult to obtain (such as victims of natural disasters or war, the homeless, and refugees). A body lice infestation may transmit more serious diseases such as typhus.
- Pubic lice or crabs prefer the genital areas, but are not limited to these regions. This type of lice is most commonly spread through sexual contact.
Lice make the host's skin itch, bringing the blood up to the surface for an easy snack. Lice treatment includes:
- Meticulous removal of visible lice and eggs from the scalp, hair, eyebrows, and eyelashes
- Over-the-counter shampoos such as NIX (permethrin) or Rid
- Ivermectin or other prescription medicines for resistant lice
To prevent reinfestation, soak combs, and brushes in hot water with the treatment shampoo and wash all hats, scarves, bedding, and clothing in hot water. Bag toys and other non-washable items for two weeks.
This burrowing mite uses the host's skin as a depository for its young larvae. Scabies mites can burrow deep into the lower layers of skin and are tough to remove. They spread through contact and will make the skin itch, especially during nighttime hours when the bug is more active. Pimples, rash, and burrows are signs of the infestation. The mites tend to infect the hands, wrists, armpits, and groin where the skin is thinner. Treatment options include:
- Prescription creams or lotions such as 25% benzyl benzoate, 5% permethrin, 1% lindane, or sulfur ointment
- Prescription Ivermectin
Disinfect all areas by vacuuming sofas, rugs, and carpets and wash clothing, linen, and other fabrics in hot water. Bag toys and other non-washable items for two weeks.
This common parasite resides in mattresses, couches, chairs, and small crevices of furniture and wallpaper. The wingless bed bugs hatch from eggs and they can survive for years in their hiding places. They bite human skin and take their nourishment from blood during the night.
Itching from the raised bumps or welts on skin and allergic reaction to the bite can be severe. Scratching of affected areas can cause the skin to get infected. Bed bug treatment includes over-the-counter topical or oral antihistamine creams or lotions and steroids for symptom relief and topical antiseptics or antibiotics to ward off infection. Wash bedding and towels hot water and dry with high heat, and encase mattresses, box springs, and pillows.
The Demodex mite lives in or near hair follicles and oil (sebaceous) glands of the skin. Human Demodex infestation have the following characteristics:
- Two species are common in humans where they are obligatory parasites and most people are carriers of the organisms.
- The larva mites spread through skin-to-skin contact. They feed on skin cells and oil and die after a few weeks in the follicles and glands.
- Demodex mites are typically found on the face in areas such as the eyebrows, eyelids, forehead, cheeks, chin, nose, ears, and in other body skin occupied by sebaceous glands.
- The bugs often cause no symptoms unless they are present in large numbers and thus cause inflammation or allergic reaction in the skin, and problems such as rosacea, loss of eyelashes, and conditions of the scalp. People with a weakened immune system are more likely to develop symptoms.
Skin conditions can be prevented by keeping skin clean, avoiding greasy creams, and exfoliating the face regularly. Treatment of symptomatic Demodex includes topical permethrin or prescription topical or oral metronidazole, or use of ivermectin in severe cases.
Chigger mites are most prevalent in tall grasses, weeds or the borders of woods. The larva infect bare feet, especially between the toes, as well as the ankles and around the waist. The mite attaches to skin and the bite causes small red pimples and severe itching. A rash can also appear on sun-exposed areas of skin. After feeding the larva falls off the skin. Treatment includes antihistamines and topical steroid creams or lotions for symptomatic relief.
Ticks attach themselves to the skin by piercing it with their jaws (mandibles), where they can feed for days. They are usually picked up while walking in the woods or bushes. The bite is likely to be painless or produce mild itching and the tick is found only by careful skin inspection. Treatment for ticks includes the searching for and removal of ticks from skin. Prompt removal with a tweezer and washing the area of skin might avoid infections such as Lyme disease or Rocky Mountain spotted fever.
The human flea is rare in North America. The dog or cat flea is most likely to bite humans in industrialized areas. They are flat, wingless parasites that can inhabit bedding and animal sleeping areas. They reproduce quickly and can jump from host to host.
Flea bites produce itchy, red bumps, often in groups. The itching can be annoying and the bumps can get infected through repeated scratching. Some people can have an allergic reaction to flea bites. To eliminate the bugs, give pets flea treatment and treat rugs, carpets, and bedding with an insecticide.
Our skin, especially warm, moist areas, can play host to a variety of fungi. Four common human infections are caused by the fungus Trichophyton. The infections include athlete's foot (tinea pedis), scalp ringworm (tinea capitis), jock (groin) itch (tinea cruris), and ringworm on other areas of the body (tinea corporis). Other fungal organisms include yeast species such as candida.
Fungi cause redness, flaking, and chronic itching of the skin. A fungus spore can pass from one person to another or pass to humans from a household pet. Infections are treated with topical antifungal creams such as clotrimazole or ketoconazole, or oral medicines.
Cutaneous Larva Migrans
Cutaneous larva migrans is caused by the hookworms that appear most frequently among dogs and cats. Infections in humans occur when skin touches infected fecal matter from pets. This type of parasite will appear as a raised, red rash or vesicles in a circular or trailing pattern. Hookworms can spread extensively and cause extreme skin itching. Treatment includes topical thiabendazole liquid or cream or oral medicines such as Ivermectin or albendazole.
This kind of infestation is caused by the maggot, or larvae, of two-winged flies. The flies lay their eggs on other insects or objects which then move on to and burrow under the skin of humans. The infestation is most common in tropical countries. Treatment is with topical or oral Ivermectin.
There are three types of cutaneous myiasis you can contract depending on the species of fly. These are boil, wound and migratory myiasis. Boil or furuncular myiasis is extremely painful and enlarges quickly. Wound myiasis makes skin rot and migratory parasites move from person to person, causing illness in hosts. Treatment includes topical or oral Ivermectin.
The screwworm is the larva of a fly that resembles a housefly that infects animals but can also affect humans. The fly lays hundreds of eggs along the edge of an open wound of animals and rarely humans. The larvae hatch from the eggs and burrow deep into the skin through a wound or body opening and destroy healthy tissue. Pustules or boils can develop from the invasion.
The screwworm maggots might drop off the skin after five to seven days of feeding or persist for a long time in the skin and deeper tissues. Treatment includes removing the maggots from the site of invasion. This parasite has been essentially eradicated from North America but was found anew in 2016 in the Florida Keys. Infestation is more common in Central America, the Caribbean, and other parts of the world.
Skin Parasites Infestations Are Common
Parasites can infect the skin of anyone of any age, race, or geographical location. Cut down on your chances of becoming infected by practicing good hygiene, washing clothing and linen frequently, and avoiding close contact with anyone who has parasites.