001683 - When Pruritus is Beyond Allergy: Waldenström Macroglobulinemia (WM) Presenting as Allergic Itch in the Community
Case report
Pruritus is commonly associated with allergic or dermatologic conditions but can occasionally signify underlying systemic diseases. This case describes a rare presentation of Waldenström macroglobulinemia (WM) manifesting as chronic pruritus.
A 76-year-old transport driver with no history of atopy, presented to an allergy community clinic with systemic itching after a COVID-19 illness, predominantly affecting his feet. There was no identifiable allergic triggers or changes in his skin care routine. Clinical exam was void of any skin allergic conditions of urticaria or eczema. Investigations into metabolic causes of pruritis revealed elevated white blood cell count, C-reactive protein, and immunoglobulin E. Symptomatic management with antihistamines and topical anti-inflammatories provided minimal temporary relief.
Persistent pruritus prompted further evaluation, which identified elevated inflammatory markers, liver enzymes, bile acids, and immunoglobulin M (IgM), raising suspicion for monoclonal gammopathy of undetermined significance (MGUS). A referral to oncology services was arranged. A subsequent bone marrow biopsy and genetics confirmed WM as the underlying diagnosis. Additional nerve conduction studies revealed abnormal nerve stimulation in the upper extremities, suggestive of neuropathic itch.
The neuropathic pruritus, attributed to gammopathy-related nerve dysfunction, was treated with Pregabalin, initially with some relief and improved significantly with chemotherapy. Pregabalin was tapered after chemotherapy.
This case highlights the importance of a multidisciplinary approach in evaluating chronic pruritus when initial allergy workup is inconclusive. Integration of systemic, metabolic, and hematologic investigations facilitated early diagnosis and effective management of this rare presentation of WM. Chronic pruritus may be an early indicator of systemic disease, underscoring the need for comprehensive evaluation in such cases.
