SHM Converge Scientific Abstract ePoster Gallery-False Accusation: A Case of Refractory Urticaria

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This case report describes a 53-year-old man who developed a widespread, intensely pruritic urticarial rash with some vesicles, along with cough, sore throat, and fever, shortly after knee replacement surgery. Because he had been taking cefadroxil postoperatively, his skin findings were initially thought to be a cephalosporin drug allergy. A respiratory pathogen panel later showed positive Mycoplasma IgM, and he was treated with doxycycline, antihistamines, and then high-dose steroids when the rash worsened and there was concern for Stevens-Johnson syndrome.<br /><br />The authors argue that the rash was more consistent with mycoplasma-associated mucocutaneous disease than a true cephalosporin allergy. They note that Mycoplasma pneumoniae can cause a range of skin manifestations, including urticaria, maculopapular eruptions, vesicular lesions, erythema multiforme, SJS, and reactive infectious mucocutaneous eruption (RIME). Because these presentations are uncommon and variable, they are often misdiagnosed as medication-related eruptions.<br /><br />The report emphasizes the importance of considering mycoplasma in patients who present with new skin lesions plus respiratory symptoms, especially when laboratory testing supports infection. Early recognition can guide appropriate treatment of both the infection and the skin symptoms, reduce unnecessary antibiotic avoidance, and prevent patients from being incorrectly labeled as allergic to an entire class of antibiotics. The authors recommend mycoplasma IgM testing in similar cases and suggest biopsy or allergy/immunology referral when the diagnosis remains uncertain.

Asset Subtitle

Apoorva Kondapally

Meta Tag

Author List Apoorva Kondapally, Caroline Caperton, Prajwal Kumsi Sreedhar, Vivek Moorthy

Category Clinical Vignettes

Concept Mycoplasma-Associated Mucocutaneous Disease

Concept Skin Eruption

Concept Mycoplasma pneumoniae infection

Concept Respiratory symptoms

Concept Acute Urticaria

Distinguished Non-Finalist

Presenter Organization Willis Knighton Medical Center

Presenting Author Apoorva Kondapally

Track Adult

Keywords

mycoplasma pneumoniae

urticarial rash

cephalosporin allergy

cefadroxil

Stevens-Johnson syndrome

reactive infectious mucocutaneous eruption

vesicular lesions

respiratory symptoms

mycoplasma IgM

drug eruption

Mycoplasma-Associated Mucocutaneous Disease

Skin Eruption

Mycoplasma pneumoniae infection

Respiratory symptoms

Acute Urticaria