The 3 variants of MIRM include:
- Classic MIRM has evidence of all 3 diagnostic criteria plus a nonmucosal rash, such as vesiculobullous lesions (77%), scattered target lesions (48%), papules (14%), macules (12%), and morbilliform eruptions (9%).4
- MIRM sine rash includes all 3 criteria but there is no significant cutaneous, nonmucosal rash. There may be “few fleeting morbilliform lesions or a few vesicles.”4
- Severe MIRM includes the first 2 criteria listed, but the cutaneous rash is extensive, with widespread nonmucosal blisters or flat atypical target lesions.4
Our patient had definitive clinical symptoms, laboratory evidence, and severe oral mucositis without significant cutaneous rash, thereby fulfilling the criteria for a diagnosis of MIRM sine rash variant.
These skin conditions were considered in the differential
The differential diagnosis for sudden onset of severe oral mucosal blisters in children includes herpes gingivostomatitis; hand, foot, and mouth disease; erythema multiforme; and Stevens-Johnson syndrome/toxic epidermal necrolysis (SJS/TEN). The presence of pulmonary symptoms and oropharyngeal mucositis, together with the laboratory markers currently proposed as MIRM diagnostic criteria, are important in helping differentiate MIRM from other items in the differential diagnosis.
Herpes gingivostomatitis would involve numerous ulcerations of the oral mucosa and tongue, as well as gum hypertrophy.
Hand, foot, and mouth disease is characterized by vesicular exanthems of the hands, legs, and buttocks.
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