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contact dermatitis
Saturday 9 April 2022
allergic contact dermatitis
| WKP | PO |
Definition : T cell-mediated delayed (type IV) hypersensitivity reaction to allergens from skin contact.
Contact dermatitis results from either exposure to allergens (allergic contact dermatitis) or irritants (irritant contact dermatitis).
Phototoxic dermatitis occurs when the allergen or irritant is activated by sunlight.
Synopsis
Acute stage :
- epidermal edema / spongiosis
- with or without prominent intercellular bridges or vesiculation
- normal basket weave orthorkeratosis
Subacute stage :
- acanthosis and epidermal edema / spongiosis
- with or without hyperkeratosis or parakeratosis
Chronic stage :
- marked acanthosis
- hyperkeratosis with or without parakeratosis
- minimal epidermal edema
Langerhans cell microabscesses can be associated with allergic contact dermatitis (ACD) but are a nonspecific finding
- Langerhans cells have abundant cytoplasm and horseshoe shaped nuclei.
See also
cutaneous diseases
