<i>Mycoplasma pneumoniae</i>-Induced Mucositis Sine Rash: <i>Case report in an adult patient</i>

We report the case of a 36-year-old male patient who presented to a tertiary care hospital at Ciudad Real, Spain, in 2024 with no significant medical history and no history of taking any medications or supplements; he was admitted to the intensive care unit due to acute respiratory failure secondary to pneumonia.The patient also presented with ocular, oral and genital lesions of 7 days' duration.On examination, bilateral conjunctival injection, erosions and haemorrhagic crusts covering a large surface of the lips, erosions affecting nasal vestibules and glans penis were noted [Figs. 1 and2].No skin lesions or epidermal detachment were noted upon examination of the palms, soles, other extremities and trunk.Polymerase chain reaction (PCR) testing for multiple respiratory pathogens was positive only for Mycoplasma pneumoniae.Oral sample PCR for herpes simplex virus was negative.Serological tests for HIV, cytomegalovirus and Epstein-Barr virus were also negative.Indirect immunofluorescence assays for antinuclear antibodies, anti-intercellular substance antibodies and anti-basement membrane zone antibodies were also negative.Based on the findings described, the most likely diagnosis was M. pneumoniae-induced mucositis without rash (MIRM sine rash).The patient was treated with azithromycin 250 mg intravenously daily for 5 days, methylprednisolone at a dose of 1mg/kg/day for 5 days as well as a topical compounded formula of 1% lidocaine with 0.1% triamcinolone acetonide for 7 days.Significant clinical improvement was observed within a week; the patient was discharged without complications after 14 days.