based solely on your description this would not be typical of chicken pox (varicella). search webmd for some more information about this now uncommon viral infection. while a child may get a mild rash about two weeks after a live vaccine like varicella it would not be typical just to get an eruption just on the toes. the chicken pox lesion is a water blister on a red base often referred to as a "dew drop on a rose petal". if it is just on his toes i would be more prone to consider a contact dermatitis from his shoes or something he came in contact with while in bare feet. since i have no way of seeing it first-hand this is just a blind guess so please follow up with his health care provider if this rash does not resolve.
rash started at base of toes and is now on thigh and some random spots on arms. could this be chickenpox? . my son is 17 months old and has had the chickenpox vaccine. looked like ant bites at first and that's what doctor thought it was. etiher that or a reaction to something he came in contact with. they prescribed hydrocortisone but it has not helped. rash is not anywhere else on feet except at toes. the rash on the thigh is pretty much a line and there are just a couple of spots on his arms. looks like pimples.