Lichenoid and Interface Dermatitis

A number of uncommon, clinically varied, and sometimes poorly understood inflammatory cutaneous diseases are linked by the presence of histologic findings classified as lichenoid and interface dermatitis. These inflammatory patterns can be seen in potentially fatal disorders like Steven-Johnson syndrome and toxic epidermal necrolysis as well as in limited diseases with minimal morbidity, such is true of fixed drug reaction. This chapter will discuss entities encompassed in these inflammatory patterns and point to clinical and histologic findings that help reaching a definitive diagnosis.