Acariasis

by S. Serkan Sezer MD

Acariasis is a general term in dermatology and parasitology that covers a range of skin disorders caused by mites and ticks. It encompasses everything from scabies, one of the commonest skin conditions worldwide, to allergic reactions provoked by house dust mites. Although these tiny creatures, often invisible to the naked eye, may appear insignificant, the conditions they produce can have a substantial impact on human health.

Definition

In English medical dictionaries, the term is transcribed as /ˌækəˈraɪəsɪs/ and defined as “the presence of mites or ticks on the skin.”

More broadly, acariasis refers to any disease or skin condition caused by infestation with — or sensitisation to — members of the Acari subclass (mites and ticks). The term derives from the Greek akari, meaning “mite,” together with the suffix -iasis, denoting a disease state.

What Are Mites and Ticks?

Mites and ticks belong to the class Arachnida, the same group that includes spiders and scorpions. They have eight legs (like spiders) and form one of the most diverse animal subclasses, comprising thousands of species. Some are completely harmless, while others can cause significant disease in humans and animals.

Mites Important in Human Health

  • Sarcoptes scabiei — the scabies mite
  • Demodex folliculorum and Demodex brevis — the demodex mites
  • Dermatophagoides species — house dust mites
  • Trombiculidae family — chiggers (harvest mites)
  • Cheyletiella — predominantly an animal mite but capable of infesting humans

Ticks Important in Human Health

  • Ixodes species — castor bean and similar hard ticks
  • Rhipicephalus species — including the brown dog tick
  • Dermacentor species
  • Hyalomma species — particularly important in some regions for transmitting Crimean–Congo haemorrhagic fever

Main Forms of Acariasis

1. Scabies

The most widely known form. It is caused by Sarcoptes scabiei, a microscopic mite that burrows into the outermost layer of the epidermis (the stratum corneum). Its features include:

  • Intense itching — characteristically worse at night
  • Burrows — fine, wavy, greyish lines, particularly between the fingers and on the wrists
  • Papules and vesicles — small red bumps and blisters
  • Typical sites — between the fingers, wrists, elbows, armpits, around the navel, groin, and genital area
  • Transmission — by close skin-to-skin contact; sometimes through shared clothing, towels, or bedding

A severe form, crusted (Norwegian) scabies, occurs in immunocompromised people and is characterised by thick crusts containing very large numbers of mites.

2. Demodicosis

The mites Demodex folliculorum and Demodex brevis live in low numbers in the hair follicles and sebaceous glands of almost every healthy adult. In some people, however, they multiply excessively and cause disease:

  • Rosacea-like rash — redness on the face
  • Demodex folliculitis — inflammation around the hair follicles
  • Blepharitis — inflammation of the eyelid margins
  • Itching and burning sensation

3. House Dust Mite Allergy

Dermatophagoides pteronyssinus and Dermatophagoides farinae are major causes of allergic disease. Their droppings and body fragments contain potent allergens that may produce:

  • Allergic rhinitis — sneezing, nasal congestion, runny nose
  • Asthma
  • Atopic dermatitis (eczema)
  • Allergic conjunctivitis

4. Chigger Bites (Trombiculiasis)

Caused by the larvae of mites in the Trombiculidae family (“chiggers” or “harvest mites”). The clinical picture is dominated by:

  • Intense itching
  • Red papules
  • Typical sites — areas where clothing is tight against the skin (ankles, waist, behind the knees)
  • Time course — symptoms usually appear several hours after exposure

5. Tick Bites and Tick-borne Diseases

Tick bites are important not only because of local skin reactions but, more importantly, because of the infections ticks can transmit:

  • Lyme disease — caused by Borrelia species
  • Crimean–Congo haemorrhagic fever
  • Tick-borne encephalitis
  • Rocky Mountain spotted fever
  • Babesiosis
  • Anaplasmosis

6. Other Forms

  • Cheyletiellosis — usually transferred from animals (especially cats and dogs) to humans
  • Grain mite dermatitis — affects people in occupational contact with stored grain
  • Bird mite dermatitis — caused by mites that migrate from bird nests to humans

Clinical Features

The features of acariasis vary with the species responsible, but several findings are common:

Skin Symptoms

  • Itching — usually the most prominent symptom; often severe
  • Redness and inflammation
  • Papules and vesicles
  • Burrows — particularly in scabies
  • Excoriations — from scratching
  • Secondary bacterial infection — areas damaged by scratching can become infected
  • Crusting and scaling

General Symptoms

  • Sleep disturbance — itching often worse at night
  • Anxiety and irritability
  • In children, restlessness and poor school performance
  • Loss of appetite

Diagnosis

The diagnosis rests on a combination of clinical and laboratory findings:

  • Detailed history — duration of symptoms, exposures, similar complaints among contacts, occupational and travel history
  • Physical examination — distribution and characteristics of the lesions, identification of typical burrows
  • Dermatoscopy — use of a dermatoscope to identify mites and their burrows
  • Skin scraping — material is scraped from the skin and examined under the microscope for mites, eggs, or faeces
  • Skin biopsy — used in selected cases
  • Allergy testing — for mite-related allergic disease, skin prick tests or specific IgE measurements
  • Examination of contacts — particularly in scabies, assessment of family members and other close contacts is important

Treatment

Treatment varies with the type of acariasis:

Scabies

  • Topical agents
    • Permethrin 5% cream — first-line treatment
    • Benzyl benzoate
    • Sulfur ointment — safer in pregnancy and very young children
    • Crotamiton
  • Oral treatment
    • Ivermectin — particularly useful in extensive or crusted scabies
  • General measures
    • Treatment of all household contacts at the same time
    • Hot washing or sealing (in plastic bags for the recommended period) of clothing and bedding
    • Treatment of itching with antihistamines

Demodicosis

  • Topical metronidazole
  • Topical ivermectin
  • Topical permethrin
  • Eyelid hygiene (in blepharitis)
  • In selected cases, oral ivermectin

House Dust Mite Allergy

  • Environmental measures
    • Mite-proof mattress and pillow covers
    • Washing bedding regularly at high temperatures (≥60 °C)
    • Reducing carpets and soft furnishings in the bedroom
    • Lowering indoor humidity
  • Medical treatment
    • Antihistamines
    • Nasal corticosteroids
    • Inhaled medications for asthma
    • Allergen-specific immunotherapy (allergy vaccination)

Chigger and Other Mite Bites

  • Symptomatic management of itching
  • Topical corticosteroids
  • Oral antihistamines
  • Treatment of secondary infection if it develops

Tick Bites

  • Safe tick removal — using fine-tipped forceps or tweezers, the tick is gripped close to the skin and removed with a steady, perpendicular pull. The tick should not be crushed, twisted, burnt, or covered with substances such as oil or alcohol.
  • Cleaning the bite site
  • Monitoring of symptoms — fever, rash, or flu-like symptoms in the weeks following the bite should prompt medical review
  • Prophylactic treatment — antibiotic prophylaxis may be considered in selected cases (for example, in areas where Lyme disease is endemic)

Prevention

Several measures help reduce the risk of acariasis:

General Measures

  • Personal hygiene
  • Regular washing of clothes and bedding
  • Cleaning of household items
  • Reducing close contact with infested individuals

Tick Protection

  • Wearing long-sleeved shirts and long trousers when walking in wooded or grassy areas
  • Tucking trousers into socks
  • Wearing light-coloured clothing so that ticks are easier to see
  • Using insect repellents containing DEET, picaridin, or permethrin (on clothing)
  • Performing a careful body check after outdoor activities
  • Showering as soon as possible after returning indoors

Indoor Measures

  • Keeping indoor humidity below 50%
  • Using a vacuum cleaner with a HEPA filter
  • Choosing mite-resistant materials in the bedroom
  • Limiting pets’ access to bedrooms

Animal Contact

  • Regular veterinary care for pets
  • Use of tick- and flea-prevention products

At-Risk Groups

Certain groups are at increased risk of acariasis or its complications:

  • Children — particularly susceptible to scabies and chigger bites
  • Older adults — especially those living in nursing homes (scabies outbreaks)
  • Immunocompromised individuals — at risk of crusted scabies
  • Healthcare workers — exposed in occupational settings
  • People in close-quarters living — schools, dormitories, military barracks, refugee settings
  • People in close contact with animals — farmers, veterinarians, livestock workers
  • People with outdoor occupations — increased exposure to ticks

When to See a Doctor

Medical evaluation is warranted in the following situations:

  • Persistent itching, particularly worse at night
  • Skin rash not responding to standard measures
  • Family members or close contacts with similar complaints
  • Fever, headache, or other systemic symptoms after a tick bite
  • Severe allergic symptoms
  • Skin lesions in young children
  • A rapidly enlarging area of redness around a tick bite

Public Health Importance

Acariasis — and scabies in particular — is a significant public health issue worldwide. It is estimated that hundreds of millions of people are affected by scabies each year, particularly in tropical regions and in crowded living conditions. Tick-borne diseases are also of major public health concern in many parts of the world.

The World Health Organization (WHO) has classified scabies as a neglected tropical disease and runs control programmes in affected regions.

Disclaimer

The information provided here is intended for general informational and educational purposes only and does not constitute medical advice, diagnosis, or treatment. If you suspect a skin disorder caused by mites or ticks, please consult a qualified dermatologist or other healthcare professional. Severe systemic symptoms following a tick bite — high fever, severe headache, widespread rash — may indicate a serious medical condition requiring urgent medical assessment. Do not rely on the content of this article when making decisions about your own or another person’s medical care.