Gamasoidosis, also known as dermanyssosis, is a frequently unrecognized form of zoonotic dermatitis, following human infestation with avian mites of the genera Dermanyssus or Ornithonyssus.

Diagnosis is challenging due to the mites' size, requiring microscopic identification by a medical entomologist, and the clinical symptoms often mimic other conditions, such as scabies or allergic reactions.

The atypical or delayed responses to mite bites, coupled with widespread ignorance and misinformation among healthcare providers, scientists, and pest control professionals, contribute to frequent underdiagnosis and misdiagnosis, hindering effective management and treatment.

Gamasoidosis is linked to avian mites infesting residential, public and agricultural spaces, with a potential health threat due to the transmission of zoonotic pathogens by D. gallinae.

Treatment involves eliminating mites from the environment—a process complicated by their resilience and rapid reproduction—and managing patient symptoms, which are typically self-limiting but may require supportive care.

[2] Individuals frequently describe repeated or long-term episodes of papular outbreaks, often appearing in clusters and accompanied by severe itching sensations.

[6] Described areas affected include the waist, trunk, upper extremities, abdomen, legs, finger webs, axillae, groin, buttocks, and face.

[11] It can also affect the scalp, with severe nighttime itching as a characteristic symptom,[12] and has been reported to infest the nares, orbits, eyelids, and genitourinary and rectal areas.

"[19] This, combined with their generalist strategy for host-seeking and the ability to digest non-avian blood, could explain their observed expansion to include mammals and humans as hosts.

The scientific literature documents medications which have been used off-label to treat the condition, including sarolaner in dogs, selamectin in cats and permethrin in horses.

[9] Bites can also be mistaken for those caused by other conditions such as cheyletiellosis (Cheyletiella), trombiculosis (Trombicula), bedbug infestations (Cimex lectularius), or urticarial dermatitis.

[31] Allergists and dermatologists should prioritize inspecting potential sources to locate, collect, and accurately identify mites, a task best handled by skilled parasitologists.

[18] As a result, in cases of unexplained bites in residential areas, the involvement of D. gallinae should always be considered,[17] especially during late spring and early summer when wild birds make their nests.

[33] In urban homes D. gallinae may be commonly found in the bedroom or where the patient sleeps, as they prefer to stay close to their host for optimal feeding.

[19] Preventing gamasoidosis in urban areas is achieved by avoiding the proliferation of avian mites, by refraining from feeding birds and utilizing nets on building terraces to deter nesting in close proximity to human homes.

This process involves identifying and removing sources of infestation, such as bird nests, and disinfecting affected areas with the help of pest control professionals.

[10] Employing a variety of techniques, following a Integrated Pest Management approach, can reduce the likelihood of major re-infestations and limit the development of resistance to specific insecticides.

[38] Attempts to eradicate infestations are often prolonged and ineffective, leading to significant financial burdens and psychological issues such as depression, particularly when patients are forced to relocate or invest heavily in pest control measures.

[10] Patients are advised to:[4] Avian mites are typically not found on human skin, as they tend to leave their host after feeding and are capable of moving with remarkable speed.

While topical antihistamines may offer temporary relief, their use is generally discouraged due to the potential risk of adverse skin reactions, such as allergic contact dermatitis.

[13] Gamasoidosis, particularly caused by D. gallinae, is source of growing concern in human medicine, due to factors such as limited awareness among medical specialists, lack of interdisciplinary collaboration, misdiagnoses, and an absence of diagnostic tools.

[19] The condition has been described as a worldwide infestation, with cases being identified in countries including Denmark, Egypt, France, Iran, Japan, Montenegro, Morocco, the Netherlands, Norway, Serbia, Turkey, and the United Kingdom.

[28] A "One Health" approach has been recommended to remedy this, with microbiologists, veterinarians, parasitologists, epidemiologists, environmental scientists, and clinicians working together to treat the disease.