A 48-year-old woman comes to the office due to a recurrent rash. Six months ago, a rash developed on her legs that she describes as "red patches with raised areas." The rash worsened that night with intense itching that disrupted her sleep. It spontaneously resolved over the next day. Since then, she has had repeated episodes of similar symptoms on her arms, legs, and back, each lasting 8-12 hours and occurring nearly every 2-3 weeks. She reports no trauma, insect bites, travel history, sick contacts, or changes in weight. Medical history is notable for hypertension treated with lisinopril. She does not use tobacco, alcohol, or illicit drugs. Temperature is 36.1 C (97 F), blood pressure is 138/77 mm Hg, and pulse is 78/min. Physical examination is within normal limits. The patient brings a photo of the rash, shown in the image below, from her most recent episode 2 days ago. Complete blood count, urinalysis, erythrocyte sedimentation rate, and liver function studies are within normal limits.
Which of the following is the best next step in management of this patient's condition?

Question

A 48-year-old woman comes to the office due to a recurrent rash.  Six months ago, a rash developed on her legs that she describes as "red patches with raised areas."  The rash worsened that night with intense itching that disrupted her sleep.  It spontaneously resolved over the next day.  Since then, she has had repeated episodes of similar symptoms on her arms, legs, and back, each lasting 8-12 hours and occurring nearly every 2-3 weeks.  She reports no trauma, insect bites, travel history, sick contacts, or changes in weight.  Medical history is notable for hypertension treated with lisinopril.  She does not use tobacco, alcohol, or illicit drugs.  Temperature is 36.1 C (97 F), blood pressure is 138/77 mm Hg, and pulse is 78/min.  Physical examination is within normal limits.  The patient brings a photo of the rash, shown in the image below, from her most recent episode 2 days ago. Complete blood count, urinalysis, erythrocyte sedimentation rate, and liver function studies are within normal limits.  
Which of the following is the best next step in management of this patient's condition?

Quizplus · Accepted Answer

Explanation: 11ec2b69_be93_7d48_8f63_8fc050422492_MD0005_00 This patient has chronic spontaneous urticaria, defined as episodic urticaria lasting >6 weeks that occurs without apparent triggers (eg, physical stimuli). As in this patient, lesions are intensely pruritic, presenting as confluent round or serpiginous erythematous plaques (ie, wheals). Individual lesions appear and enlarge over minutes to hours before disappearing within 24 hours. Some 40% of cases are also accompanied by angioedema. Chronic spontaneous urticaria is idiopathic 80%-90% of the time, and the diagnosis is based on clinical findings. However, because of its association with atopic and rheumatologic diseases, a limited laboratory evaluation consisting of complete blood count, inflammatory markers, liver function studies, and urinalysis is recommended, especially when other symptoms (eg, arthritis, weight loss, fever) are present. More detailed testing is not generally necessary. (Choice A) C1 esterase inhibitor levels are decreased in hereditary angioedema, which typically causes angioedema of the throat, tongue, or lips without urticaria. Patients can also have abdominal pain due to angioedema of the intestinal mucosa. (Choice C) An elevated serum antinuclear antibody level is one of the diagnostic criteria for systemic lupus erythematosus (SLE), which can be associated with chronic urticaria. However, this patient has no other clinical findings (eg, malar rash, arthritis, serositis) of SLE. (Choice D) Tryptase is a biomarker for mast cells, and elevated levels can be seen in systemic mastocytosis. However, this patient lacks the syncope, flushing, hypotension, vomiting, or abdominal pain typically seen with excessive histamine release. (Choice E) Skin biopsy is not required to diagnose chronic urticaria unless systemic symptoms (eg, abdominal pain, fever, weight loss), atypical symptoms (eg, pain instead of pruritus, petechiae/purpura, individual lesions persisting >24 hr), or elevated inflammatory markers are present to suggest urticarial vasculitis or mastocytosis. Lesions that do not respond to treatment also warrant biopsy. Educational objective: Chronic spontaneous urticaria presents with pruritic wheals that occur episodically over >6 weeks. A total of 80%-90% of cases are idiopathic, but some are associated with atopic or rheumatologic disorders. A limited laboratory workup (eg, complete blood count, inflammatory markers, liver function studies, urinalysis) is recommended to assess for potential underlying disorders. References: Chronic spontaneous urticaria: the devil's itch. (http://www.ncbi.nlm.nih.gov/pubmed/30033911)

A 48-Year-Old Woman Comes to the Office Due to a Recurrent