# Refractory and Recurrent Skin Manifestations in an Adult With Selective Immunoglobulin M Deficiency

## TL;DR

A 47-year-old woman with a rare immune disorder had recurring fevers and severe skin issues, highlighting the need to check IgM levels in similar cases.

## Contribution

This case report presents a rare instance of sIgMD with refractory skin manifestations and allergic features.

## Key findings

- The patient had sIgMD with normal B cell surface IgM but low serum IgM.
- Her skin issues and elevated IgE/eosinophils suggest an allergic component.
- The case emphasizes the importance of IgM testing in patients with recurring fevers and skin problems.

## Abstract

Selective immunoglobulin M (IgM) deficiency (sIgMD) is a rare immunodeficiency disorder characterized by decreased serum levels of IgM. Symptoms of sIgMD include repeated infections and allergic manifestations such as asthma and allergic rhinitis. The etiology and pathology of sIgMD remain largely unknown. Moreover, no genetic cause of sIgMD and associated symptoms has been established. Herein, we describe a 47-year-old female with sIgMD who presented with repeated fevers of unknown cause since childhood. She was referred to our department because of recently developed severe dermatitis without a history of atopic dermatitis or asthma. In addition to histological evaluation by skin biopsy, immunological parameters were investigated in her peripheral blood, and the cellular immunity profile was determined by flow cytometry. The patient with refractory skin manifestations was found to have sIgMD with normal surface levels of IgM in the B cells. Along with recurrence and exacerbation in dermatitis, she showed an increase in peripheral blood eosinophils and serum IgE levels, suggesting an underlying allergic mechanism. The present case strongly indicates the importance of measuring serum IgM levels when seeing patients with recurring fever and intractable skin manifestations.