Psoriasis | + | Diffuse | Regular | Thin | + | Decreased or absent | Increased mitoses; minimal spongiosis | – |
Drug reaction | + | Focal | Regular and irregular | Normal or thick | − | Normal | Spongiosis; eosinophilic infiltrate | Inflammatory cell exocytosis; single keratinocyte necrosis |
Chronic allergic/contact and atopic dermatitis | + | Focal; crust may be present | Irregular | Normal or thick | – | Normal | Spongiosis; eosinophilic infiltrate | – |
Fungal infection | Compact | Focal; crust may be present | Irregular | Normal or thick | − | Normal | Occasional neutrophilic exocytosis; | – |
LSC | + | Focal; thick crust | Regular or irregular | Thin or thick | − | Thickened; hypergranulosis | ±minimal exocytosis | – |
Scabies | + | Focal or diffuse | Irregular | Normal or thick | − | Normal | Exocytosis; eosinophilic spongiosis | – |
Seborrheic dermatitis and HIV dermatitis | + | Focal | Irregular | Normal or thick | − | Normal | Spongiosis; lymphocytic and neutrophilic infiltrate | – |
PRP | Compact | Shoulder parakeratosis*; alternating orthokeratosis and parakeratosis | Regular or irregular | Normal or thick | − | Normal | Spongiosis; lymphocytic exocytosis; rare acantholysis | Occasional vacuolar change |
PR | + | Focal | Irregular | Normal or thick | − | Normal | Small foci of spongiosis; lymphocytic exocytosis | Occasional necrotic keratinocytes |
Syphilis | + | Focal | Regular or irregular | Normal or thick | − | Normal | Lymphocytic and neutrophilic exocytosis | Interface change |
PLC | + | Caps of parakeratosis | Irregular | Normal | − | Normal | Mild spongiosis, lymphocytic exocytosis; necrotic keratinocytes | Necrotic keratinocytes |
MF | + | Focal | Regular or irregular | Normal | − | Normal | Minimal or no spongiosis; ±Pautrier microabscess | Atypical lymphoid cells lining the dermo–epidermal junction |