Some researchers have discovered that SCN9A gene mutations may be connected with primary EM.To date, few studies possess investigated the prevalence of EM in western countries. A report conducted in Norway approximated that the annual incidence was 2/100,000. In a population-based research of EM in america, the reported annual incidence was 1.3/100,000, and the overall annual population-based incidence of EM in Sweden was 0.36/100,000. Although data on the prevalence of EM are very limited, it really is proposed that EM could be more common than thought previously. In China, Zhu reported the initial medical EM case in 1945 and the first epidemic EM event in 1960.This brand-new research expands understanding of the risks of drug resistance connected with single-dose nevirapine, but as mentioned by all three study groups, the scientific implications for patients are not yet clear. More research will be needed to determine whether nevirapine utilized to prevent mother-to-child transmission affects the probability of successful treatment afterwards with nonnucleoside reverse transcriptase inhibitors, the class of medication to which nevirapine belongs.