Experiences of patients with cutaneous manifestations of monoclonal gammopathy of undetermined significance (MGUS): Insights from the first disease-specific support group

Monoclonal gammopathy of undetermined significance (MGUS) is a clonal plasma cell disorder characterized by monoclonal immunoglobulins or an abnormal ratio of free immunoglobulin light chains in blood or urine. Affecting 5% of adults aged 50 and older, MGUS is often asymptomatic and is typically incidentally diagnosed. In most cases, it requires only conservative observation and follow-up. However, MGUS may result in severe complications, such as significant cutaneous morbidity, which is not currently considered part of the diagnostic ‘requirement’ for multiple myeloma.^{1, 2}

Dermatologic manifestations linked to MGUS, which we named ‘gammopathic dermopathy’, include cutaneous light chain amyloidosis, POEMS syndrome, and scleromyxedema, among others.^3-6 Despite their existence, cutaneous MGUS manifestations remain poorly understood, leading to diagnostic delays and patient morbidity.^{7, 8}

While there are numerous multiple myeloma support groups, no official groups exist for those with MGUS. These patients struggle to find appropriate care and have difficulty obtaining effective medications because of the lack of diagnostic recognition, challenges with insurance coverage, and increased cost of medications. Thus, we organized the inaugural support group through Columbia Dermatology for patients with gammopathic dermopathy, titled ‘MGUS 4 Us’, to better understand the experiences of these patients.

Ten patients attended the meeting, sharing stories that highlighted common themes such as uncertainty and confusion about diagnosis, challenges in communicating diagnoses with families, difficulties in finding doctors with expertise, and struggles in obtaining effective treatment.

All 10 patients completed an optional survey with skin conditions reported including eczema, pyoderma gangrenosum, and scleromyxedema (Table 1). Notably, at least five patients experienced skin symptoms without an established diagnosis. Symptoms included itching (70%), pain (20%), rash (20%), and tightness (10%). Timelines varied, with one patient recently diagnosed with MGUS, five diagnosed 1–5 years ago, three diagnosed 5–10 years ago, and one diagnosed over 10 years ago. Two patients developed skin symptoms this year, three developed symptoms 1–5 years ago, two developed symptoms 5–10 years ago, two developed symptoms over 10 years ago, and one was unknown.

Of the 10 patients, six received treatment for skin symptoms, including topical steroids (4), multiple myeloma drugs (lenalidomide/ixazomib, 2), hydroxychloroquine (1), intravenous immunoglobulin (1), oral steroids (1), antibiotics (1), and dupilumab (1). While one patient reported feeling ‘a lot better’ after treatment, three felt ‘a little better’, two reported no change, and four did not receive treatment. The survey also revealed that most patients had dermatologists, oncologists, haematologists or rheumatologists involved in their care.

The most bothersome feelings about their skin related to quality of life included: frustration, annoyance, concern about appearance, worry, embarrassment, burning or stinging sensations, depression, and condition persistence. Conversely, showing affection and difficulty in working or enjoying activities were least bothersome.

This support group underscores the need for specialized care for patients with gammopathic dermopathy, emphasizing the range of skin conditions and symptoms, particularly pruritus and pain. Skin symptoms often precede MGUS diagnosis, suggesting that MGUS should be investigated during evaluation of persistent skin conditions. Patients shared quality of life concerns ranging from embarrassment to worry to depression, which are important to ask about and address directly in patient visits. The experiences shared by patients underscore the significant morbidity, diagnostic challenges, and potential treatments for gammopathic dermopathy, demonstrating the importance of increased research into this rare condition. It has been reported that patients with gammopathic dermopathy who were treated with multiple myeloma drugs improved, suggesting that these treatments may be considered for patients with refractory skin disease, especially given their favourable side-effect profile.⁹ Overall, this highlights the importance of interdisciplinary care and dermatologists in addressing significant challenges to quality of life for patients with gammopathic dermopathy.

Emily R. Gordon gathered and analysed data. Larisa J. Geskin have given substantial contributions to the conception and the design of the manuscript, Caroline Chen, Oluwaseyi Adeuyan, Brigit A. Lapolla, Megan H. Trager, Celine M. Schreidah, and Lauren M. Fahmy assisted the above authors with acquisition, analysis and interpretation of the data. All authors have participated in drafting the manuscript, Emily R. Gordon and Megan H. Trager revised it critically. All authors read and approved the final version of the manuscript.

LJG has served as an investigator for and/or received research support from Helsinn Group, J&J, Mallinckrodt, Kyowa Kirin, Soligenix, Innate, Incyte, Trillium, Merck, BMS, and Stratpharma; on the speakers’ bureau for Mallinckrodt and Recordati; and on the scientific advisory board for SciTech and Celsyntec. EG, CC, OA, BL, MT, LF, CS have no conflicts of interest to declare.

Not applicable.