An article published in American Family Physician reported that pruritus can be a symptom of a distinct dermatologic condition or of an occult underlying systemic disease. It was stated that of the patients referred to a dermatologist for generalized pruritus with no apparent primary cutaneous cause, 14 to 24 percent have a systemic etiology. It was suggested that in the absence of a primary skin lesion, the review of systems should include evaluation for thyroid disorders, lymphoma, kidney and liver diseases, and diabetes mellitus. While findings suggestive of less serious etiologies include younger age, localized symptoms, acute onset, involvement limited to exposed areas, and a clear association with a sick contact or recent travel. In addition, chronic or generalized pruritus, older age, and abnormal physical findings heightens the risk for underlying systemic conditions. Initial evaluation for systemic disease should involve complete blood count and measurement of thyroid-stimulating hormone, fasting glucose, alkaline phosphatase, bilirubin, creatinine, and blood urea nitrogen. Moreover, Hodgkin’s lymphoma – a malignant disease, is strongly associated with pruritus, which affects about 30 percent of patients with pruritus; chest radiography is needed when lymphoma is suspected. Furthermore, a wheal and flare response indicates histamine-induced pruritus in patients with urticaria or an allergic dermatitis. It was discussed that such patients benefit from continuous dosing of a long-acting antihistamine. Second-generation antihistamines, such as fexofenadine, may be more effective because of improved patient compliance.(1)

Reference

1. Reamy BV, Bunt CW, Fletcher S. A diagnostic approach to pruritus. American Family Physician. 2011 Jul 15;84(2).