Uniformed Services University of the Health Sciences, Bethesda, MD 21037, USA.
Am Fam Physician. 2011 Jul 15;84(2):195-202.
Pruritus can be a symptom of a distinct dermatologic condition or of an occult underlying systemic disease. Of the patients referred to a dermatologist for generalized pruritus with no apparent primary cutaneous cause, 14 to 24 percent have a systemic etiology. 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. 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. Chronic or generalized pruritus, older age, and abnormal physical findings should increase concern for underlying systemic conditions. Initial evaluation for systemic disease includes complete blood count and measurement of thyroid-stimulating hormone, fasting glucose, alkaline phosphatase, bilirubin, creatinine, and blood urea nitrogen. Hodgkin lymphoma is the malignant disease most strongly associated with pruritus, which affects up to 30 percent of patients with the disease. Chest radiography is needed when lymphoma is suspected. A wheal and flare response indicates histamine-induced pruritus in patients with urticaria or an allergic dermatitis. These patients benefit from continuous dosing of a long-acting antihistamine. Second-generation antihistamines, such as cetirizine, loratadine, and fexofenadine, may be more effective because of improved patient compliance.
瘙痒可能是一种明确的皮肤病的症状，也可能是一种隐匿性的潜在系统性疾病的症状。在因全身性瘙痒而被转诊至皮肤科医生处就诊、且没有明显原发性皮肤病因的患者中，有 14%至 24%存在系统性病因。在没有原发性皮肤损害的情况下，系统回顾应包括甲状腺疾病、淋巴瘤、肾脏和肝脏疾病以及糖尿病的评估。提示不太严重病因的发现包括年龄较小、局部症状、急性发作、局限于暴露部位的受累以及与患病接触者或近期旅行的明确关联。慢性或全身性瘙痒、年龄较大以及异常的体格检查结果应增加对潜在系统性疾病的关注。系统性疾病的初始评估包括全血细胞计数和促甲状腺激素、空腹血糖、碱性磷酸酶、胆红素、肌酐和血尿素氮的测量。霍奇金淋巴瘤是与瘙痒关系最密切的恶性疾病，多达 30%的患者会出现瘙痒。当怀疑淋巴瘤时，需要进行胸部 X 线检查。当存在荨麻疹或过敏性皮炎时，风团和红斑反应表明是由组胺引起的瘙痒。这些患者受益于长效抗组胺药的持续给药。第二代抗组胺药，如西替利嗪、氯雷他定和非索非那定，由于改善了患者的依从性，可能更有效。
