A previously healthy 51‐year‐old man presented to our institution with a 6‐month history of intermittent rash. He described his rash as 2‐3 centimeter raised, red, pruritic lesions occurring on the face, extremities, back and torso almost every day. The rash occurred without any obvious trigger and resolved in 2‐3 hours. He denied associated facial edema, shortness of breath, wheezing, fever, arthralgia, abdominal pain or diarrhea. He was unemployed and denied any environmental exposures or pets. He used over‐the‐counter diphenhydramine which partially relieved his pruritus. Physical examination was unremarkable, however pictures of his rash was consistent with urticaria. Initial laboratory investigation, including complete blood count, blood chemistry, liver enzyme, anti‐nuclear antibody, complement levels, thyroid function tests and viral hepatitis profile were all unremarkable except for low C4 level (<6 mg/dL). He was initially diagnosed with chronic idiopathic urticaria and treated with daily fexofenadine and montelukast. He returned in 1 month without any improvement of symptoms. Further laboratory investigation, including repeated anti‐nuclear antibody, anti double‐stranded DNA, anti‐Ro/SSA, anti‐La/SSB and serum electrophoresis (SPEP), were obtained and, interestingly, his SPEP revealed a monoclonal spike of IgG Kappa. He underwent bone marrow biopsy which showed plasma cells of 40%. He was ultimately diagnosed with multiple myeloma and successfully treated with chemotherapy and autologous stem cell transplantation. His urticaria resolved after treatment for the multiple myeloma
Chronic urticaria is a common disorder with estimated prevalence of 1% in adults. Several illnesses can contribute to chronic urticaria, however, even with extensive investigation only 10‐20% of patients have an identifiable cause. Monoclonal gammopathy, either from monoclonal gammopathy of undetermined significance, Waldenstrom macroglobulinemia or multiple myeloma, is an uncommon cause of chronic urticaria. The mechanism by which monoclonal gammopathy causes urticaria remains unclear but appears to be related to immunoglobulin deposition and subsequent complement activation within the skin basement membrane and capillary wall.
Our case underscores the importnace of multiple mylemoa as a potential cause of urticaria. Screening for monoclonal gammopathy with an SPEP in every case might not be cost‐effective but should be considered in patients who fail to respond to standard treatment.
To cite this abstract:Ungprasert P, Leeaphorn N, Srivali N. Deeper Than Skin; What Lies Beneath the Chronic Urticaria?. Abstract published at Hospital Medicine 2014, March 24-27, Las Vegas, Nev. Abstract 662. https://www.shmabstracts.com/abstract/deeper-than-skin-what-lies-beneath-the-chronic-urticaria/. Accessed December 10, 2018.