  We examine the role of seesaw motivated exotic scalars in loop-mediated Higgs
decays. We consider a simple TeV-scale seesaw model built upon the fermionic
quintuplet mediator in conjunction with the scalar quadruplet, where we examine
portions of the model parameter space for which the contributions of charged
components of the scalar quadruplet significantly increase the $h \to \gamma
\gamma$ decay rate. The most significant change in the diphoton width comes
from a doubly charged scalar \Phi^{--} which should be the lightest component
in the scalar quadruplet. There is a mild suppression of the $h \to Z \gamma$
decay width by a factor 0.9 -- 0.7 in the part of the parameter space where the
$h \to \gamma \gamma$ decay width is enhanced by a factor 1.25 -- 2.

High Energy Physics - Phenomenology