Nocturnally pruritic rash
Quick thinking and fast reflexes during the physical exam led to an identification that confirmed the diagnosis.
Diagnosis: Gamasoidosis
The collected sample (FIGURE 2) was examined and identified as an avian mite by a colleague who specializes in entomology, confirming the diagnosis of gamasoidosis.
Two genera of avian mites are responsible: Dermanyssus and Ornithonyssus. The most common culprits are the red poultry mite (D gallinae) and the northern fowl mite (O bursa). These small mites parasitize birds, such as poultry livestock, domesticated birds, and wild game birds. When unfed, the mite appears translucent brown and measures 0.3 to 0.7 mm in length, but after a blood meal, it appears red and increases in size to 1 mm. The mites tend to be active and feed at night and hide during the day.2 This explained the severe nighttime pruritus in this case.
Human infestation, although infrequent, can be a concern for those who work with poultry, or during the spring and summer seasons when young birds leave their nests and the mites migrate to find alternative hosts.3 The 1- to 2-mm erythematous maculopapules are often found with excoriations in covered areas.3,4 Unlike scabies, the genitalia and interdigital areas are spared.3,5
Differential for arthropod dermatoses
The differential diagnosis includes cimicosis, pulicosis, pediculosis corporis, and scabies.
Cimicosis is caused by bed bugs (from the insect Cimex genus). Bed bugs are oval and reddish brown, have 6 legs, and range in size from 1 to 7 mm. Most bed bugs hide in cracks or crevices of furniture and other surfaces (eg, bed frames, headboards, seams or holes of box springs or mattresses, or behind wallpaper, switch plates, and picture frames) by day and come out at night to feed on a sleeping host. Commonly, bed bugs will leave a series of bites grouped in rows (described as “breakfast, lunch, and dinner”). The bites can mimic urticaria, and bullous reactions may also occur.2
Continue to: Pulicosis
