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Approaching the Pruritic Patient

»What is the most common symptom of dermatologic disease?
»What is an “itch”?
»Is an itch a separate modality of pain or a submodality of pain?
»What causes an itch?
»Describe the difference between localized and generalized pruritus.
»What is the best approach to evaluation of a patient with localized pruritus?
»What are the common causes of localized pruritus?
»What is notalgia paresthetica?
»What is the physician’s best approach when seeing a patient with generalized pruritus?
»After obtaining a complete history and physical examination, what clinically oriented classification scheme should be followed?
»What are common causes of generalized pruritus?
»How prevalent is an underlying systemic disease in a patient who seeks medical attention for pruritus?
»What is “winter itch”? In which patient population is it common?
»The patient complains that “wool makes me itch” or “I am allergic to wool.” What disease does this patient probably have?
»What treatment should the physician consider if a patient presents with pruritus and “hives”?
»What disease should the physician consider if the patient volunteers that his spouse also suffers from itching?
»Is pruritus in HIV-infected patients common? What are the common causes of pruritus in these patients?
»Which psychiatric disorder often presents with intractable pruritus?
»Which patients with renal failure experience “renal itch”?
»Which patients with liver disease are most likely to experience pruritus? What is the best screening laboratory test?
»What are the common causes of cholestic pruritus?
»Which hematologic disorders are known to present with pruritus?
»Is generalized pruritus a common symptom of endocrine disorders?
»Can itching cause skin disease?
»What is the best symptomatic treatment for a patient with pruritus?

 
 
 

Which psychiatric disorder often presents with intractable pruritus?

Delusions of parasitosis is the fixed belief that a patient is infested with living organisms in the absence of evidence of such infestation. Delusions of parasitosis often occurs as a sole psychological disturbance, but it may be associated with an underlying personality disorder, such as the obsessive-compulsive type. A physician must take care not to miss a true infestation. A careful history, thorough examination of the skin, microscopic review of “bugs” brought in by the patient, and, occasionally, a biopsy of the “bite” sites is needed. Establishing a dermatology-psychiatry liaison is helpful in establishing a diagnosis and selecting therapy. The neuroleptic pimozide, a blocker of dopamine receptors, is considered an effective treatment but requires careful monitoring because of several potentially serious side effects.

Driscoll MS, Rothe MJ, Grant-Kels JM, Hale MS: Delusional parasitosis: a dermatologic, psychiatric, and pharmacologic approach, J Am Acad Dermatol 29:1023–1033, 1993.