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Common skin conditions
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For each of the ten cases, study the image(s) and then answer the questions. You can click on the image to view a larger version if required.
Each case should take approximately five minutes to complete. There is a list of suggested further reading material at the end of the quiz.
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What is the name of this cutaneous sign?
Erythema nodosum
What underlying conditions may be present?
Erythema nodosum is a reactive process of unknown pathogenesis in which there is an inflammatory infiltrate in the subcutaneous tissue. In New Zealand, the most common identified precipitating causes are antecedent streptococcal infection, and sarcoidosis. Pregnancy, the oral contraceptive pill, inflammatory bowel disease, tuberculosis and other infective organisms are occasionally implicated. In 50% of cases the cause is not identified.
What investigations should be performed?
Investigations are indicated to determine the underlying cause where possible. Useful tests include chest X-ray, complete blood count, urinalysis, throat culture, antistreptolysin-O titre, tuberculin skin test.
What symptomatic treatment should be advised?
Resting and elevating the affected areas relieves swelling and discomfort. Nonsteroidal inflammatory drugs are helpful. Oral potassium iodide 300mg tid for one to four weeks is often successful. Specific treatment of identified underlying disease is essential.