Grand Rounds

Reactive Infectious Mucocutaneous Eruptions: Diagnostic Challenges

Sofia Maria da Silva Faria¹, Ana Rita Barroca de Macedo¹, Nuno Miguel Sanches de Almeida², Ana Luísa Figueira de Sousa Correia¹, Rui Manuel Correia de Almeida^1
1Pediatrics Department, Hospital Pedro Hispano, Unidade Local de Saúde de Matosinhos, Matosinhos, Portugal, ²Pediatrics Department, Centro Hospitalar de Vila Nova de Gaia-Espinho, Unidade Local de Saúde de Gaia/Espinho, Vila Nova de Gaia, Portugal

Address for Correspondence: Sofia Maria da Silva Faria, Unidade Local de Saúde de Matosinhos, Hospital Pedro Hispano, Rua de Dr. Eduardo Torres, 4464 - 513 Senhora da Hora, Portugal. Email: sofiasilvafaria@gmail.com

Keywords: Mycoplasma pneumoniae, Human metapneumovirus, Mycoplasma pneumoniae induced rash and mucositis, reactive infectious mucocutaneous eruptions (rime), Pediatric mucositis.

Clinical Problem:
An 11-year-old girl with a past medical history of stomatitis three months earlier, presented to the emergency department with five days of mouth pain, partial food refusal, genital burning and eye itching. She also had a productive cough for the past ten days.
On the first day of mouth pain, she was diagnosed with aphthous stomatitis at the emergency department and given supportive treatment (pain management, frequent mouth hygiene, hydration and mucosal care). Forty-eight hours later, due to the persistency of symptoms and complete food refusal, she was evaluated by her attending pediatrician, who prescribed topical betamethasone, oral acyclovir (20 mg/Kg/dose every 6 hours), oral azithromycin (10 mg/Kg/dose, once a day) and topical hyaluronic acid.
Her condition worsened and she returned to the emergency department on the fifth day of mouth pain. Upon admission, she had no fever. Physical examination revealed hemorrhagic crusts on her lips (Figure 1), gingivitis, sloughing of the lips and tongue and conjunctival hyperemia in her left eye, but no other skin lesions, including on her genitals.
A complete blood analysis and urine test were performed, both showing no significant abnormalities. A chest radiography was also done and showed a bronchovascular reinforcement. Additionally, multiplex Polymerase Chain Reaction (PCR) panel testing for respiratory viruses was negative for SARS-CoV-2, influenza A and B and respiratory syncytial virus. The on-call ophthalmologist diagnosed blepharitis and superior tarsal conjunctival ulcers in her left eye. Due to complete food refusal, intravenous fluid therapy was implemented and she was hospitalized in our pediatric facility.
During inpatient care, an expanded multiplex PCR panel for identification of respiratory pathogens tested positive for human metapneumovirus and serologic tests were collected at admission.
Due to RIME suspicion, dermatology was consulted. Skin swab samples were collected and analyzed via PCR, which were negative for Herpes simplex type 1 and 2, Mycoplasma pneumoniae and Chlamydia pneumoniae. Serologic tests were positive for immunoglobulin G for Herpes simplex type 1, positive for immunoglobulin M and G and for Mycoplasma pneumoniae and equivocal immunoglobulin M but positive immunoglobulin G for Chlamydia pneumoniae.
She completed seven days of oral acyclovir, five days of oral azithromycin, four days of oral betamethasone seven days of oral sucralfate, seven days of topical fusidic acid and eight days of ophthalmic ointment (containing prednisolone, neomycin and sulfacetamide).
Within a week, there was noticeable clinical improvement, with healing of the mouth ulcers, pain relief, as well as increased appetite. She was discharged home at the seventh day of hospitalization, in excellent condition. She was posteriorly followed up in a pediatric consultation and was discharged after 9 months without new episodes. No blood tests were performed.

Figure 1. Hemorrhagic crusting of upper and lower mucosal lips.

What is the significance of detecting human metapneumovirus in this patient and how does it support the diagnosis of RIME over other infectious mucocutaneous conditions?