What is Prurigo Simplex?

Prurigo simplex is an itching skin disorder characterized by extremely itchy skin lesions and nodules. The direct cause of prurigo simplex is usually not known, but some factors are known to trigger or aggravate it. This condition falls between chronic and acute, sometimes transitioning to a chronic condition. Many people experience a recurrence of the condition after periods of remission. Middle-aged patients are the age group most prone to this condition.

The most common symptoms of prurigo simplex are skin nodules that resemble intensely itchy insect bites. These nodules are frequently scratched and develop into lesions that continue to itch. Sometimes the skin thickens and becomes discolored around the nodules. The scalp, arms, legs and trunk of the body are the most frequent sites of blows and injuries. The itching can become severe and habitual, worsening the condition and possibly causing infection in the open sores.

Sometimes the nodules become less itchy and eventually disappear leaving behind a discolored area or scar tissue. However, the same nodules can persist for months or even years without healing. Patients may experience a remission, but then relapse with the formation of new nodules. The condition can also become chronic, without periods of improvement and relief.

Although the exact causes of prurigo simplex have not been determined, it is believed that there are many aggravating factors that can trigger the condition. Extremes of cold, heat, or sunlight are factors in some cases. Food, drug, and other allergies can trigger prurigo simplex. The condition also appears to be triggered or aggravated by emotional stress. Chronic infections such as sinusitis and endocrine or metabolic disorders may also play a role.

Prurigo simplex treatment is sometimes difficult, as common treatments for other skin conditions are not always effective. Corticosteroid creams and ultraviolet light treatments sometimes work. A promising treatment is psoralen photochemotherapy in the form of psoralen ultraviolet A (PUVA) aluminum bath. The patient is bathed in a psoralen solution and then exposed to ultraviolet A radiation in a series of treatments. Psoralen is a plant-derived compound that makes cells more sensitive to the effects of ultraviolet light.

Additional treatments for prurigo simplex include steroid injections into the nodules, as well as antihistamines and tranquilizers. Patients are advised to avoid strong sunlight, extreme temperatures, and activities that cause the body to overheat. If emotional stress is one of the triggers, learning how to manage stress can help relieve symptoms. Determining if allergies are contributing to the problem, then avoiding the allergen could result in improvement of prurigo simplex.

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