Evidence shows that erythema toxicum neonatorum (ETN) has been described in the literature since the 15th decade as a primarily rash in pediatric patients. Clinical studies show that the lesion of ETN is mainly characterized by the presence of minute yellowish papules and pustules that are usually surrounded by an irregular reddish wheal. It should be noted that evidence also demonstrated the pathology of these lesions is temporary and usually disappears within a few hours. In the present literature review, we discussed the etiology, prevalence, risk factors, and clinical signs of ETN based on findings from relevant research. The etiology of ETN is not clear among the different studies. However, some studies show involvement of immune and potential allergic reactions. The prevalence of the condition among infants is also remarkably variable among the relevant studies worldwide. There is also inconsistency in reporting the significance of the risk factors related to the prevalence and severity of the condition. On the other hand, the clinical signs among studies seem to be consistent and easily detected except when evaluating dark-skinned infants. Further studies are needed better to understand the etiology and epidemiology of the condition.

Evidence indicates that Maturity-onset diabetes of the young (MODY) exhibits an autosomal dominant inheritance and is the most common type of monogenic diabetes. However, it should be noted that misdiagnosis of the condition is very common, as patients are usually mistaken for both types I and type II diabetes mellitus. In the present study, we have discussed the etiology, pathogenesis, and epidemiology of MODY based on an extensive literature review. Genetic mutations are mainly attributed to the development of the disease, which usually manifests throughout the second to fifth decades of life. Pancreatic islet cell destruction, impaired insulin secretion, defects regarding threshold to serum glucose levels, and other pathological events are usually observed in these patients. Data regarding the epidemiology of the condition is not adequately reported in the literature, especially among non-European populations, indicating the need to conduct future investigations. Ethnic and age variations are potentially epidemiological characteristics of the disease. However, not enough data are present in the literature to support such conclusions.