Final answer:
The Koebner phenomenon is the term used to describe the formation of new psoriatic plaques at sites of skin trauma in patients with psoriasis.
Step-by-step explanation:
A patient who develops new psoriatic plaques over areas of skin trauma is exhibiting the Koebner phenomenon. This response is named after the dermatologist Heinrich Koebner, who first described it. When an individual with psoriasis experiences skin trauma, such as a cut, burn, or abrasion, it can lead to the formation of psoriatic skin changes at the site of the injury. The Koebner phenomenon can occur in other skin conditions as well but is particularly associated with psoriasis.