This document defines and describes interface dermatitis. It notes that interface dermatitis involves inflammation along the dermoepidermal junction associated with vacuolation of basal keratinocytes. The key morphological changes include basal cell vacuolation, apoptotic keratinocytes, obscuring of the dermoepidermal junction, various epidermal changes, and papillary dermal changes. Interface dermatitis can be subdivided into a primarily vacuolar type with little inflammation or a primarily lichenoid type with lymphocytes directly destroying basal keratinocytes.

1. By
Dr.LAXMI PRASANNA
PG FIRST YEAR
REFERENCES :
IADVL
FITZPATRICKS
ROOKS

2.  Definition : Inflammation along the dermoepidermal junction associated
with Vacuolation characterizes interface dermatitis
 This common type of reaction leads to papules or plaques in some skin
diseases & bullae in others
 Interface dermatitis includes conditions in which the primary
pathology involves the "interface," i.e., the dermo-epidermal
junction. The components of this "interface" include the basal
layer of the epidermis, the dermo-epidermal junction, the
papillary dermis, and the adventitial dermis around the adnexal
struc
 Interface dermatitis includes conditions in

3.  Interface dermatitis include conditions in which primary pathology
involves interface i.e DEJ
 The components of interface includes basal layer of the epidermis ,
DEJ , Papillary dermis , adventitial dermis along the adnexal
structures
 Pathophysilogically apoptosis , individual cell necrosis of
keratinocytes is the most prominent feature of the primary interface
dermatitis
 T – cell mediated cytokine damage is major mechanism resulting in
disease

4. MORPHOLOGICAL CHANGES :
 Basal cell vacuolation
 Apoptotic keratinocytes / Colloid bodies / civatte
bodies
 Obscuring of DEJ
 Epidermal changes
 Papillary dermal changes

5. 1. Basal cell vacuolation :
 Most prominent feature , includes small basal or sub-basal vacuoles
 There is expansion of cytoplasm leads to partial / complete
destruction of basal cells , which appears as squamisation of basal
layer .

6. APOPTOTIC BODIES :
 Small rounded eosinophilic hyaline anucleared structures &
slightky smaller than basal cells
 They are present individually or clumps in basal layer , papillary
dermis or spinous layer .
 Sometimes as whorls in acrosyringia & in s.c

7. OBSCURING OF DEJ :
 Lymphocytes are the major cells in interface dermatitis other cells
like eosinophils ,neutrophils , mast cells also seen .
 Accumulation of lymphocytes along basal layer obliterates the
distinction b/w epidermis & papillary dermis
 Inflammatory infiltrates may vary depending on disease & its stage
may be from sparse ( pauci inflammatory ) to dense band like (
lichenoid ) infiltrate

8. EPIDERMAL CHANGES :
 A thin flat atropic epidermis is typical for SLE
 Epidermal acanthosis with hypergranulosis & thick Compact
orthokeratotic stratum corneum is seen in LICHEN PLANUS
 Remarkable irregular hyperplasia in verrucuous discoid lupus

9. PAPILLARY DERMAL CHANGES :
 It undergoes expansion to accommodate inflammatory infiltrate
 The effect of long standing infiltrate results in fibrosis & sclerosis
 Dense infiltrate arranged in band like i.e lichenoid type
 2nd basal damage leads to incontinence of melanin into papillary
dermis

10. Morphologically this pattern subdivided into.
1.primarily vacuolar : (degeneration of basilar keratinocytes. with
little or no inflammation.
Interface dermatitis, vacuolar type.A Erythema multiforme with target
lesions. B Vacuolar alteration along the dermalepidermal junction in
association with exocytosis of lymphocytes and several necrotic
keratinocytes

12. 2 . primarily lichenoid : (with lymphocytes directly engaged in the
destruction of basilar keratinocytes
Interface dermatitis, lichenoid type. A Lichen planus. B Band-like
infiltrate of lymphocytes that obscures the dermal–epidermal
junction in addition to jagged epidermal hyperplasia, hypergranulosis
and melanophages.

14.  frequently there is overlap between these two categories.
 even though an entity has lichenoid features histologically (e.g. fixed drug
eruption),
 That doesn’t mean it must resemble lichen planus clinically.
 Also, some degree of lichenoid inflammation can be associated with a
variety of benign and malignant neoplasms of the skin – e.g. solitary
lichenoid keratosis and melanoma, respectively.

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