Abstract
As the skin ages, a deficiency in collagen occurs, thus injectable collagen products
have become a sensible and popular option for dermal filling and volume enhancement.
Several types of collagen have been developed over the years, including animal sources
such as bovine and porcine collagen, as well as human-based sources derived from pieces
of the patient's own skin, cadaver skin, and later cultured from human dermal fibroblasts.
While collagen overall has a relatively safe, side effect profile, there are several
complications, both early and late onset, that practitioners and patients should be
aware of. Early complications, occurring within days of the procedure, can be divided
into non-hypersensitivity and hypersensitivity reactions. The non-hypersensitive reactions
include injection site reactions, discoloration, maldistribution, infection, skin
necrosis, and the very rare but dreaded risk of vision loss, whereas the hypersensitivity
reactions present usually as delayed type IV reactions, but can also rarely present
as an immediate type I reaction. Late complications, occurring within weeks to even
years after injection, include granuloma formation, foreign body reactions, and infection
secondary to atypical mycobacteria or biofilms. This review will give a detailed overview
of the complications secondary to cutaneous collagen injections.
Keywords
collagen - dermal fillers - injections - complications
