DISTINGUISHING POLYCYTHEMIA FROM ALLERGIC PRURITUS

Abstract

<h3>Introduction</h3> An abnormally high isolated red blood cell count is known as polycythemia. Polycythemia is caused by genetic mutations like JAK2 or secondary causes such as sleep apnea, COPD, etc. A clinical presentation that should lead to a high index of suspicion for the condition is generalized pruritus and erythema, especially following hot showers. <h3>Case Description</h3> Patient is a 49-year-old male with a past medical history significant for anxiety, erectile dysfunction, sleep apnea, and atopic dermatitis who was referred to the allergy clinic for skin rash and generalized pruritus. The generalized pruritus has occurred for the past 3 months, typically occurs during hot showers, and is associated with erythema of the skin. He denies any associated symptoms, and ROS is otherwise negative. CBC results demonstrated: RBC 6.50, HGB: 19.3, HCT: 55.3. The patient denied previous myocardial infarction, cerebrovascular accident, venous thromboembolism, and erythromelalgia. Repeat CBC showed decreased HGB and HCT of 18.0 and 53.6. Evaluation for JAK2 mutation was negative. <h3>Discussion</h3> This clinical presentation is consistent with polycythemia likely due to secondary causes. Interestingly, he has not experienced any complications typically associated with polycythemia such as stroke, myocardial infarction, and venous thromboembolism. This can be attributed to his consistent efforts to donate blood, every 45 days since the age of 18. As allergists and primary care providers, we should have a high index of suspicion for polycythemia with patients who present with generalized pruritus and erythema following a hot shower.