How is nodular prurigo caused?

Nodular prurigo, also known as nodular lichen, is a verrucous nodule damage. The etiology and pathogenesis are not completely clear at this stage. It is believed that it is related to allergy, gastrointestinal dysfunction, endocrine disorders and autoimmune factors after insect bites. It starts as reddish papules, rapidly transforms into hemispherical nodules, soybean to broad bean size, top corners turn into verrucous appearance, rough surface, scattered distribution, and hard texture. Due to intense itching, it can show epidermal exfoliation, scratches, blood scab, etc. Good hair in the skin of the limbs, especially the leg parts. The course of disease is generally chronic, repeated attacks, delay does not heal.