INDIANAPOLIS – , in a single-center retrospective study. In addition, 71% of patients with recurrent disease experienced 1-2 recurrences – episodes that were generally milder and occurred at variable intervals.
Those are among key findings from the study of 50 patients with RIME, presented by Catherina X. Pan at the annual meeting of the Society for Pediatric Dermatology.
Catherina X. Pan
Reactive infectious mucocutaneous eruption (RIME) is a novel term encompassing an array of rare, parainfectious mucositis diseases, noted Ms. Pan, a fourth-year medical student at Harvard Medical School, Boston. Previously known as Mycoplasma pneumoniae-induced rash and mucositis (MIRM), common clinical characteristics of RIME include less than 10% body surface area involvement of polymorphic skin lesions (vesiculobullous or targetoid macules/papules); erosive oral, genital, and/or ocular mucositis involving more than two sites, and evidence of prior infection including but not limited to upper respiratory infection, fever, and cough.
In addition to M. pneumoniae, other pathogens have been implicated, she said. “While the underlying etiology of the disease is not entirely clear, it’s become increasingly known that RIME tends to recur in a subset of patients.”
A cohort study of 13 patients with RIME found that Black race, male sex, and older age were predominant among the five patients who developed recurrent disease.
The estimated recurrence rate is between 8% and 38%, but the clinical characteristics of patients who develop recurrent RIME tend to be poorly understood, Ms. Pan said.
Along with her mentor, Sadaf Hussain, MD, of the department of dermatology at Boston Children’s Hospital, Ms. Pan conducted a retrospective chart review to characterize the clinical history and course of disease in patients diagnosed with recurrent RIME. They extracted data between January of 2000 and March of 2022 using ICD-10 codes used by board-certified dermatologists at Boston Children’s Hospital, as well as a text search for RIME or MIRM in the dermatology notes. Patients were included if they had a RIME/MIRM diagnosis by a board-certified dermatologist and/or infection on PCR/serology and mucositis involvement with limited skin involvement.
The study population included 50 patients: 24 with recurrent RIME and 26 with isolated RIME. The majority (66%) were male, and the mean age of RIME onset was between 11 and 12 years old, which is up to two years younger than previously reported in the case series of 13 patients. Most of the study participants (79%) were White, but there were no significant differences in patients who had recurrent RIME and those who had isolated RIME in terms of age, sex, or race.
Isolated vs. recurrent RIME
However, compared with patients who had isolated RIME, a greater proportion of those with recurrent RIME had a history of atopic disease (46% vs. 23%, respectively; P = .136), as well as a history of tonsillectomy and adenoidectomy (25% vs. 4%; P = .045). “This has not been previously observed, but it may generate a hypothesis that patients with a history of frequent infection as well as amplified immune responses may be associated with disease recurrence,” Ms. Pan said.
The average number of episodes among patients with recurrent RIME was 3.5 and the interval between episodes was variable, at a mean of 10.2 months. Ms. Pan reported that 71% of recurrent RIME patients experienced 1-2 episodes, although one patient experienced 9 episodes.
Clinically, episodes among all patients with RIME were characterized by infectious prodromal symptoms (69%), oral lesions (95%), ocular lesions (60%), genital lesions (41%) and cutaneous lesions (40%). However, RIME recurrences were less severe and more atypical, with 49% involving only one mucosal surface and 29% involving two mucosal surfaces. Also, except for oral lesions, rates of infectious prodromal symptoms and other lesions significantly decreased among recurrences compared with initial RIME.
“Notably, we found that M. pneumoniae was the most common known cause of RIME, particularly among the initial episodes,” Ms. Pan said. “However, 61% of recurrent RIME episodes did not have a known cause in terms of infectious etiology. And, concordant with prior studies, we also found decreased severity [of RIME recurrences] as indicated by decreased rates of emergency department presentation, hospitalization, and duration of hospitalization.”
In other findings, psychiatric complications such as anxiety and depression followed the onset of RIME in 33% of those with recurrent disease and 22% of those with isolated disease. In addition, the three most common treatments among all 50 patients were systemic steroids, topical steroids, and M. pneumoniae-specific antibiotics.
“While RIME is considered as typically milder than Stevens-Johnson syndrome and toxic epidermal necrolysis with low mortality rates, it can lead to severe complications including conjunctival shrinkage, corneal ulceration and scarring, blindness, and oral, ocular, urogenital synechiae,” Ms. Pan noted. “Increased use of corticosteroids and steroid-sparing agents such as IVIG have also been observed. Multidisciplinary care with ophthalmology, urology, and mental health services is critical.”
She acknowledged certain limitations of the study, including its retrospective, single-center design, and the possibility that milder cases may have been excluded due to a lack of accurate diagnosis or referral.
Carrie C. Coughlin, MD, who was asked to comment on the study results, pointed out that nearly half (24) of patients in the cohort experienced recurrent RIME. “This is a high proportion, suggesting counseling about the possibility of recurrence is more important than previously thought,” said Dr. Coughlin, director of the section of pediatric dermatology Washington University/St. Louis Children’s Hospital.
“Fortunately, recurrent cases tended to be less severe. However, many patients had more than one recurrence, making this challenging for affected patients.”
The researchers reported having no financial disclosures. Dr. Coughlin is on the board of the Pediatric Dermatology Research Alliance (PeDRA) and the International Immunosuppression and Transplant Skin Cancer Collaborative.