Definition of altruism : Regard for others, both natural and moral; devotion to the interests of others.

Seems to me to be doing something for others (anyone) without expecting to be rewarded. Yes it might make you feel good (and thus technically be a 'reward') and that is what doing something selfless should do.

These "attachments" to others of doing stuff because of attachments to these others still falls under the characteristic of altruism... but they are not the only form of altruism. And if someone thinks they are, well, that is just sad, because doing stuff for others unconditionally is quite nice.