Prurigo Nodularis

Prurigo nodularis is a chronic inflammatory skin disease marked by intense itching and firm, symmetrically distributed papules or nodules on the skin, thought to arise from a combination of a defective skin barrier, an overactive type 2 immune response, and remodeling of the nerve structures in the affected skin. Diagnosis is clinical, based on the characteristic appearance and distribution of the lesions together with the pattern of severe, long-lasting itch. Much of that itch runs through pathways that do not respond to histamine, which is why antihistamines are generally ineffective against it, and the disease tends to be chronic, resistant to standard treatment, and prone to recurrence. It affects roughly 0.083 percent of people globally, mostly adults and older people, more often women, and Black patients are affected at up to three times the rate of other groups. Because the relentless itch-scratch cycle can be so disruptive, treatment usually needs to address the skin lesions, the nerve-related itch, and associated problems such as anxiety, depression, and sleep disturbance together, and secondary bacterial infection from scratching is a recognized complication.