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Case Note

Case Note: Itchy Lesions

History

A 42-year-old woman with no associated symptoms of fever, arthralgias or shortness of breath. She has no significant past medical history or current disease. A detailed history and physical exam does not reveal signs of local disease. She takes occasional ibuprofen for headaches.

Initial evaluation

  • 2-month history of intermittent pruritic lesions on back, chest, arms, occasionally on legs
  • Lesions are migratory, lasting 1 day

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Enter your diagnosis

Diagnosis

  • A diagnosis of urticaria is rendered

Further to the case in question, general evaluation strategy for urticaria is provided below.


Differential diagnosis

It is imperative to determine whether the patient has urticaria alone or a more systemic presentation with possible progression to angioedema or anaphylaxis. Careful review of symptoms of anaphylaxis, such as tongue, lip or facial swelling, shortness of breath or wheezing and diarrhea is necessary. Angioedema is characterized by deep tissue swelling (ie, dermal or subcutaneous edema), pain more than itching, involvement of mucous membranes and resolution that is slower than for urticaria (which typically resolve in <24 hours); angioedema typically takes up to 72 hours to resolve.

Initial Treatment

  • Start fexofenadine 180 mg daily
  • Discontinue ibuprofen
  • Follow-up evaluation at 2 weeks

Follow-up evaluation strategy

At Week 2:

  • Patient reports slight improvement of intermittent urticaria but is still having multiple episodes since last clinic visit
  • Escalate dose of fexofenadine
  • Blood test: Complete blood count with differential, erythrocyte sedimentation rate
  • Follow-up evaluation at 4 weeks

At Week 4:

  • Patient reports ongoing improvement
  • Blood test results show slightly elevated erythrocyte sedimentation rate (ESR)
  • Add montelukast 10 mg daily
  • Follow-up evaluation at 4 weeks (improved)

General discussion

Acute urticaria

Acute urticaria is a common disorder of skin, with a lifetime prevalence estimated at 20%. Patients with acute urticaria typically present with migrating pruritic edematous papules and plaques of variable size, surrounded by erythema or an area of vasoconstriction (ie, wheal). They may be intermittent, with the skin returning to normal appearance in less than 24 hours. They result from a variety of causes, including drug reactions, food allergy, systemic disorders and infection; the underlying cause may be undetermined in many cases. Following discontinuation or avoidance of the inciting agent, the majority of acute reactions resolve within days to weeks. Therefore, therapy is symptomatic and attempts to suppress symptoms until urticaria abates.


Chronic urticaria

Chronic urticaria represents approximately 25% of all cases of urticaria and is defined as urticaria when lasting longer than 6 weeks; the cause is often not found. Chronic urticaria may be idiopathic or found in association with underlying systemic diseases such as infection (bacterial, fungal, parasitic, viral), autoimmune disease (including production of auto-antibodies against the IgE receptor, triggering mast cell degranulation) or drug reaction. Whereas foods may be a relevant trigger for acute urticaria, the role of food allergies in chronic urticaria is controversial; a consistent, reproducible trigger is often not identified. As chronic urticaria may stem from an underlying systemic illness, it is important to perform a complete history and physical examination and pursue only basic laboratory testing and relevant diagnostic considerations. Although underlying malignancy was previously believed to be a cause of chronic urticaria, prior recommendations for diagnostic malignancy work-up are no longer supported by recent evidence. The goal of therapy is to provide relief of symptoms.

Further reading

Khan DA. Chronic urticaria: diagnosis and management. Allergy Asthma Proc 2008;29:439-46.

Peroni A, et al. Urticarial lesions: If not urticaria, what else? The differential diagnosis of urticaria. Part I, II. J Am Acad Derm 2010;62:541-70.

Zuberbier T, et al. Guideline: Management of urticaria. Allergy 2009;64:1427-43.

Zuberbier T, et al. Guideline: definition, classification and diagnosis of urticaria. Allergy 2009;64:1417-26.

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