User blog comment:Xilinoc/Ch. 552 - The Fundamental Virulence/@comment-1333438-20131008152852/@comment-493809-20131008160640

For hybrids/half-bloods like Ichigo and Uryu, the rules may be different. For pure Quincies, however, it's likely a serious problem.

When Quilge used Sklaveri on Ayon, he wore it like a monster suit. It also wore off quickly. It could be that the hollow reiatsu actually merging with the Quincy is what causes the problem.

Likewise, Ichigo's mom was suffering from the Hollow infection due to her pure blood, but once she and Isshin were connected, the collective soul stabilized. Also, White was designed to infect his targets with his reiatsu - normal hollow wounds may not work that way.

The nature of Zangetsu (here referring to both Old Guy and Hollow Ichigo) reflects Ichigo's own fusion between species/powers. Shinigami powers seem to be similar to a focused version of Hollow powers - having the Shinigami element in his soul creates stability of a sort.