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A 79-year-old woman comes to your office to discuss her "itching." Although her skin is extremely pruritic all over, she has never noticed a rash. The itching does not wake her from sleep, although it is worse in the evening. She has tried "scrubbing her skin" with antibacterial soap and taking hot showers to get "very clean," but this has not helped the itching.
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- What additional questions would you ask to learn more about her pruritus?
- How do you classify pruritus without a rash?
- Can you make a definite diagnosis through an open-ended history followed by focused questions?
- What laboratory tests may be needed to rule out serious etiologies of pruritus?
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Pruritus, or itching, is the most common dermatologic complaint. Pruritus can occur in the presence or absence of cutaneous findings. For the purpose of this chapter, the focus will be on evaluating pruritus in the absence of any other cutaneous manifestations. Patients with pruritus should be evaluated carefully because it may be the presenting symptom of a serious underlying problem. The prevalence of an underlying systemic illness causing the pruritus ranges from 10% to 50%. Meticulous history taking will determine the extent of work-up that is warranted. Asking appropriate questions will reduce the amount of testing required to discover the etiology of the pruritus.
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Pruritus without cutaneous findings is usually generalized. Localized pruritus may be due to postherpetic neuralgia, brachioradial pruritus, notalgia paresthetica, or venous insufficiency. Brachioradial pruritus is an intense itching of the forearms suspected to be due to nerve damage. Notalgia paresthetica is a neuropathic disorder of the infrascapular back area that often presents with pruritus. When pruritus is localized in the perianal or genital areas, it can be due to diabetes and is associated with poor diabetic control. For example, vulvar pruritus occurs in 18.4% of diabetic women.1
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Generalized itch may be due to an underlying internal disease, psychiatric illness, xerosis (dry skin), or senescence. Systemic diseases associated with generalized pruritus include malignancies, hematologic disease, hepatobiliary disorders, infections, endocrine disturbances, and renal disease.
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Retrospective studies estimate the prevalence of underlying malignancy in patients with pruritus to range from 2% to 11%.2,3 Etiologies include direct tumor invasion, distant metastases, paraneoplastic phenomenon, nerve compression, cholestasis, and side effects of treatment. ...