The purpose of a wound dressing is primarily to protect the wound from infection and further harm, while stopping or containing bleeding or exudation, and to aid the healing process. There are a variety of dressings that serve different purposes that can be used on diabetic wounds.
Hydrogel dressings allow partial aeration of the wound, contain exudation, and moisturize the wound. They contain exudates, which help the body break down necrotic tissue. Hydrogels can be used on infected wounds as studies have shown they do not aid bacterial growth.
In case of diabetic dressings, hydrogels are most effective when a necrotic wound has been debrided using surgical instruments (sharp debridement). However they must be used with discretion for diabetics with reduced blood flow to the limbs. This is because the moisturizing properties of the hydrogels are likely to macerate the surrounding tissue and a dry gangrenous condition in a patient might quickly progress to wet gangrene, which is much worse.
Hydrocolloids are similar to hydrogels in all properties except moisturization of wounds. While they do not add their own moisture to the wound, they do trap exudates within the wound, leasing to a moist condition, similar to using hydrogels. While this can help the body in the destroying necrotic tissue, it can also, when used on highly exuding wounds, lead to the softening of the skin and tissue around the wound.
Most medical authorities opine that the use of hydrocolloids on infected wounds is not advisable as it can increase the infection and the probability of developing an infection in a wound. Dressings using hydrocolloids can be kept on the wounds for much longer than regular dressings, for up to a week. So, wounds requiring regular examination do not benefit from hydrocolloid use.