What is Interface Dermatitis?
Interface dermatitis (ID) is a reaction pattern seen in skin biopsies characterized by damage to the dermo-epidermal junction and keratinocyte alterations. This damage is typically mediated by an inflammatory infiltrate that targets the
basal layer of the epidermis.
Histological Features
Histologically, ID is identified by the presence of lymphocytic inflammation at the
dermo-epidermal junction, vacuolar alteration of basal keratinocytes, and apoptotic keratinocytes known as
Civatte bodies or colloid bodies. The epidermis may also exhibit
hyperkeratosis, parakeratosis, and spongiosis.
Common Conditions Associated with Interface Dermatitis
Pathophysiology
The pathophysiology of ID involves an immune-mediated attack on the basal keratinocytes, often involving
cytotoxic T-cells. These T-cells recognize antigens presented by the
major histocompatibility complex (MHC) on basal keratinocytes, leading to
apoptosis of these cells. This process disrupts the integrity of the dermo-epidermal junction, resulting in the characteristic histological features.
Diagnostic Techniques
Diagnosis of ID is primarily made through
skin biopsy and subsequent
histological examination. Special stains and immunofluorescence may be used to identify specific patterns and immune deposits. For example, direct immunofluorescence can be helpful in diagnosing lupus erythematosus by demonstrating
immune complexes at the dermo-epidermal junction.
Clinical Presentation
Clinically, ID presents with a variety of cutaneous manifestations depending on the underlying condition. Common features include erythematous papules, plaques, and
vesicles. The lesions may be itchy or painful and are often symmetrically distributed.
Therapeutic Approaches
Treatment of ID varies based on the underlying cause but generally involves
immunosuppressive or
immunomodulating agents. Topical corticosteroids, systemic corticosteroids, and other immunosuppressants like
cyclosporine or
methotrexate may be used. It is crucial to identify and treat the underlying condition to manage ID effectively.
Prognosis
The prognosis of ID depends on the underlying etiology and the patient's response to treatment. Conditions like lichen planus and lupus erythematosus may have a chronic course requiring long-term management, whereas erythema multiforme often resolves spontaneously.
