The Seven L’s of Superficial and Deep Perivascular Mononuclear/Lymphoid Infiltrates

Abstract

The mnemonic 7 L’s has been used to prompt the histological differential diagnosis of a superficial and deep perivascular mononuclear and lymphoid infiltrate. The presence of prominent superficial dermal edema should prompt a consideration of polymorphous light eruption; whereas extension of the infiltrate to involve the adnexal structures, particularly the eccrine units supports a diagnosis of lupus. The presence of eosinophils and reactive follicles may be seen in cutaneous lymphoid hyperplasia, particularly if the etiology is a persistent reaction to arthropod bite.