Response to 'COVID-19-associated multisystem inflammatory syndrome in adults with Kawasaki disease-like cutaneous manifestations': reply from the authors.

Dear Editor, We appreciate the interest shown by Pathania regarding our manuscript, and enjoyed reading his additional comments on multisystem inflammatory syndrome in adults (MIS‐A) and children (MIS‐C) and Kawasaki disease (KD).

Our patient had a 3‐day history of fever, and the rash appeared within a day of the fever. The fever and rash subsided promptly with intravenous steroids (hydrocortisone 100 mg every 8 h), which was given as emergency treatment due to the suspicion of drug rash (azithromycin and mefenamic acid taken for the fever). By the time we examined the patient, the rash had faded and was hence not documented.

However, for the benefit of our readers, we would like to append the clinical image of rash in another case of MIS‐A with circulatory shock. The rash was morbilliform and involved the limbs and trunks, and was associated with limbus‐sparing conjunctivitis, lip crusting and palmoplantar erythema (Figure 1). The rash faded immediately with the administration of systemic steroids. The rash did not leave any postinflammatory sequelae.

Figure 1

Rash in a patient with multisystem inflammatory syndrome in adults. (a) Limbus‐sparing conjunctivitis with morbilliform rash on the face. (b) Morbilliform rash on the forearm.

We would like to clarify regarding the author’s argument of labelling features in MIS‐A as complete or incomplete KD. We agree that an abnormal immune response like T helper‐17‐mediated cytokine storm is implicated in the causation of KD as well as MIS, and some initial reports of MIS‐A resorted to mentioning the symptom complex as complete or incomplete KD. However, these are distinct clinical entities. While the classic definition of KD relied entirely on mucocutaneous manifestations, the World Health Organization definition of MIS‐C relied more on systemic signs, and laboratory markers with mucocutaneous manifestations altogether were taken as a single nonmandatory criterion. The Centers for Disease Control and Prevention definition of MIS‐A does not include cutaneous features at all. Jiang et al. have tabulated the differences between the classic definitions of KD and MIS‐C. In summary, while KD may lead to some systemic complications, especially cardiovascular phenomena, MIS presents with systemic features. Hence, some authors consider MIS as a constellation of KD and toxic shock syndrome.

As the author highlighted, MIS‐A should be considered a differential diagnosis, and immunological markers for COVID‐19 should be ordered when adult patients present with KD‐like cutaneous manifestations. However, there is no particular relevance to the complete or incomplete presentation of KD in MIS‐A.