key: cord-1009585-5t0z5ceg authors: Hosseini, Mohammad-Salar title: Kawasaki or Kawasaki-like disease? A debate on COVID-19 infection in children date: 2020-12-07 journal: Clin Immunol DOI: 10.1016/j.clim.2020.108646 sha: 523452a99b9010e60acf3f97e3ef498e24038943 doc_id: 1009585 cord_uid: 5t0z5ceg Kawasaki disease (KD) is an inflammatory syndrome which is generally observed among children. Considering the significant number of COVID-19-positive children presenting with the manifestations of typical/atypical KD, it has been mentioned as a possible complication of COVID-19 infection among the children. However, many of the reported cases do not completely fill the clinical diagnostic criteria, which has made some researchers use the term “Kawasaki-like disease” instead of KD for this state. The current manuscript aims to review the key studies in the field, address the ongoing conflict, and indicate the objective requirements of the further studies. Kawasaki disease (KD) is a form of vasculitis, usually observed among children less than five years old, which affects the middle-sized arteries. Since the delay in diagnosis of KD leads to life-threatening complications, such as coronary artery abnormalities, valvular heart diseases, Kawasaki disease shock syndrome (KDSS), and macrophage activation syndrome (MAS), an early and accurate diagnosis of KD is vital. For this purpose, diagnostic criteria have been introduced to clinically define KD, including the presence of fever for five days or more, along with at least four of the following five features [1]: 1. Conjunctivitis: Bilateral, dry, and painless 2. Cervical lymphadenopathy: Unilateral, tender, and over 1.5 cm 3. Polymorphous exanthema: Rash through trunk and extremities 4. Mucosal changes: Including strawberry tongue, hyperemia of lips, or erythema of oropharynx 5. Changes in extremities: From erythema and painful edema to desquamation A fever of fewer than five days, accompanied by two or three of the mentioned criteria is considered as incomplete (atypical) KD [1] . Also, the diagnosis could be confirmed with less than four features, if coronary artery aneurysm is present. Since the declaration of COVID-19 pandemic, there have been numerous reports of COVID-19-positive children, presenting with typical/ atypical KD manifestation. Since the KD is unknown in etiology, SARS-CoV-2 has been considered to be a cause for KD among children [2] . In general, even the number of patients presenting with clinical manifestations of KD are dramatically increased; for example, a rise of 497% in KD patients was observed in a hospital in France during the previous months [3] . However, many of the reported cases do not completely fill the clinical diagnostic criteria. Therefore, some researchers have suggested the term "Kawasaki-like disease" instead of KD. Similarly, there have been novel explanations too. Diorio et al. assessed the data of twenty-four patients with positive SARS-CoV-2 RT-PCR or serum immunoglobulin G, and observed that the children infected with SARS-CoV-2 might not show the signs and symptoms of COVID-19, but develop the clinical features of socalled, Multisystem Inflammatory Syndrome in Children (MIS-C); suggesting that MIS-C and COVID-19 are different and separate presentations of infection with SARS-CoV-2 [4] . Although the reports of patients with both MIS-C and COVID-19 manifestations make this hypothesis less likely, the essence of the fact that SARS-CoV-2 could result in such complications cannot be ignored [5] . Table 1 presents some of the main studies reporting COVID-19-positive children with clinical features in favor of KD. As seen, there is excessive conflict regarding this issue. Although substantial evidence suggests that the present condition may be different from other pediatric inflammatory disorders, we still cannot draw a precise line between them and separate similar disorders assuredly [6] . Since the diagnosis of KD is exclusively based on clinical judgement, large-scale studies are best tools to define the current inflammatory disorder or even improve the previous definition of KD, as they benefit from a greater population, along with an integrated and equivalent clinical evaluation of patients. There has been no financial support regarding the preparing and publication of this manuscript. The author declares no competing interests. 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