Table 2: Variables causing problems in differential diagnosis.

Clinical features
 Similarity and overlapping of clinical features
 Coexistance of different diseases
 Colonization and/or superinfection
 Absence of late changes in the neonate (scar formation, pigmentation changes, nail dystrophy)
Diagnostical methods
 Sample (site of sample not representative, secondary alterations)
 Timepoint of sample collection (i.e., higher herpes simplex virus load in early vesicles)
 Sensitivity and specifity of method
 Technical problems (wrong transportation media, )
 Experience in interpreting the results