Serious adverse events were rare; occurred in both the tacrolimus and corticosteroid groups; and in most cases, were considered to be unrelated to the treatment. No cases of lymphoma were noted in the included studies nor in the non-comparative studies. Cases were only noted in spontaneous reports, cohorts, and case- control studies. Systemic absorption was rarely detectable, only in low levels, and this decreased with time. Exception is made for diseases with severe barrier defects, such as Netherton's syndrome, lamellar ichthyosis, and a few others, with case reports of a higher absorption. We evaluated clinical trials; case reports; and in vivo, in vitro, and animal studies; and didn't find any evidence that topical tacrolimus could cause skin atrophy .