Dermatology - Pruritus: By Aaron Drucker M.D.

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Dermatology - Pruritus: What You Need to Know
Whiteboard Animation Transcript
with Aaron Drucker, MD
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Pruritus - or itching - is a common symptom in many skin diseases. It can be incredibly debilitating with a major impact on quality of life.
When assessing patients with generalized itch, it is important to distinguish 2 main types of pruritus: pruritus from a skin disease, or from another cause, including thyroid, liver and kidney problems, and cancer.
The first group are patients who are itchy because they have a skin disease, or a “rash”. These patients should have some signs of inflammation in their skin, such as redness, scaling, or edema. For these patients, treating the skin disease should also treat their itch.
The second group consists of patients who are itchy without having a skin disease. These patients will either have normal appearing skin, or will have changes in their skin from scratching. Clues to scratching include erosions in a linear array and the “butterfly sign”, when there is sparing of the scratch marks on areas of the back that are difficult to reach.
When you determine that a patient is itchy without having a skin disease, the next step is to determine the cause of their itch. Itch can be the result of many internal diseases, including renal failure, liver obstruction, thyroid disease, and cancers such as lymphoma.
These patients need a thorough review of systems to search for an underlying cause. They also need a lab workup, including tests of renal and thyroid function, liver enzymes, bilirubin, and bile acids, as well as a complete blood count.
If any underlying disorder is found it should be treated. However, generalized itch is often idiopathic and in that case must be treated symptomatically.