School of Medicine and Health Sciences Poster Presentations

Title

A Case of Mistaken Identity: HSP Masquerading as Urticaria

Poster Number

210

Document Type

Poster

Status

Medical Student

Abstract Category

Clinical Specialties

Keywords

Henoch-Schonlein purpura, rash, pediatrics, vasculitis, urticaria

Publication Date

Spring 2018

Abstract

An 8-year-old boy with an atopic history presented to the ED with back pain, cough, diarrhea and two weeks of bruising and arthralgias. He denied fevers, abdominal pain, or gross hematuria. Vital signs were normal. His elbows, knees and ankles were tender to palpation without restricted range of motion. Skin exam was notable for petechiae, palpable purpura, ecchymoses at various stages of healing, and evanescent urticarial plaques on the trunk, upper and lower extremities, buttocks, and genitalia. CBC, CMP, coagulation studies, ANA, RF, lyme serologies, and urinalysis were normal. C4 complement was low and ASO titers were elevated.

Punch biopsies showed peri- and intravascular infiltrate of neutrophils and eosinophils involving the superficial and deep vascular plexuses. Direct immunofluorescence (DIF) demonstrated IgA vascular deposition. These findings are consistent with Henoch-Schonlein purpura (HSP).

HSP is the most common small vessel vasculitis in children. Clinical presentation classically includes palpable purpura, arthritis, abdominal pain, and nephritis, though not necessarily concurrently. On skin biopsy, HSP demonstrates a neutrophilic infiltrate and IgA deposition in the superficial to mid-dermal vessels. HSP is a self-limited disorder, but 2% of patients will have permanent renal sequelae; thus, close follow-up is required. Our patient had atypical HSP, in which the cutaneous manifestation included urticaria.

HSP typically follows an upper respiratory tract infection but can also follow exposure to other infectious agents. Mucosal IgA and microbial antigen complexes disseminate hematogenously and deposit in vessel walls, inducing complement activation, mast cell degranulation, and neutrophil chemotaxis. Proteolytic enzymes cause vessel wall damage, resulting in palpable purpura. Superficial vessel involvement leads to urticaria and purpura while deep vessel involvement leads to bullous or necrotic lesions. Similar to HSP, acute urticaria develops after exposure to an infectious agent, medication, or allergen. The binding of these substrates to mast cells causes histamine release and leakage of plasma into the dermis. This creates classic erythematous and evanescent wheals.

Conditions associated with immune dysregulation are found in a significant number of HSP patients. Our patient’s history of atopy may have played a role in his unusual cutaneous features. We present this case to highlight an atypical presentation of HSP involving urticaria.

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A Case of Mistaken Identity: HSP Masquerading as Urticaria

An 8-year-old boy with an atopic history presented to the ED with back pain, cough, diarrhea and two weeks of bruising and arthralgias. He denied fevers, abdominal pain, or gross hematuria. Vital signs were normal. His elbows, knees and ankles were tender to palpation without restricted range of motion. Skin exam was notable for petechiae, palpable purpura, ecchymoses at various stages of healing, and evanescent urticarial plaques on the trunk, upper and lower extremities, buttocks, and genitalia. CBC, CMP, coagulation studies, ANA, RF, lyme serologies, and urinalysis were normal. C4 complement was low and ASO titers were elevated.

Punch biopsies showed peri- and intravascular infiltrate of neutrophils and eosinophils involving the superficial and deep vascular plexuses. Direct immunofluorescence (DIF) demonstrated IgA vascular deposition. These findings are consistent with Henoch-Schonlein purpura (HSP).

HSP is the most common small vessel vasculitis in children. Clinical presentation classically includes palpable purpura, arthritis, abdominal pain, and nephritis, though not necessarily concurrently. On skin biopsy, HSP demonstrates a neutrophilic infiltrate and IgA deposition in the superficial to mid-dermal vessels. HSP is a self-limited disorder, but 2% of patients will have permanent renal sequelae; thus, close follow-up is required. Our patient had atypical HSP, in which the cutaneous manifestation included urticaria.

HSP typically follows an upper respiratory tract infection but can also follow exposure to other infectious agents. Mucosal IgA and microbial antigen complexes disseminate hematogenously and deposit in vessel walls, inducing complement activation, mast cell degranulation, and neutrophil chemotaxis. Proteolytic enzymes cause vessel wall damage, resulting in palpable purpura. Superficial vessel involvement leads to urticaria and purpura while deep vessel involvement leads to bullous or necrotic lesions. Similar to HSP, acute urticaria develops after exposure to an infectious agent, medication, or allergen. The binding of these substrates to mast cells causes histamine release and leakage of plasma into the dermis. This creates classic erythematous and evanescent wheals.

Conditions associated with immune dysregulation are found in a significant number of HSP patients. Our patient’s history of atopy may have played a role in his unusual cutaneous features. We present this case to highlight an atypical presentation of HSP involving urticaria.