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Skin-nontumor / Clinical Dermatology

Other dermatoses

Allergic Contact Dermatitis

Reviewer: Mowafak Hamodat, MB.CH.B, MSc., FRCPC, Eastern Health, St. Johns, Canada (see Reviewers page)
Revised: 16 July 2011, last major update July 2011
Copyright: (c) 2002-2011, PathologyOutlines.com, Inc.


● Due to topically applied antigens, such as poison ivy or nickel, which cause delayed hypersensitivity reaction with itching or burning
● Dermatitis occurs at site of contact
● Antigens are initially taken up by Langerhans cells and carried to lymph nodes
● Upon reexposure, cytokines are released, causing endothelial activation and adherence of memory T cells, which release lymphokines, causing spongiotic dermatitis
● May get bacterial superinfection (impetiginization)

Case reports

● 30 year old with exposure to textile dyes (Dermatology Online Journal 7(1):9)

Clinical images

Linear demarcation due to textile dyes

Due to hair dye

Various images

Micro description

● Extensive spongiosis, initially acute spongiotic dermatitis, evolving into subacute or chronic spongiotic dermatitis, which then resolves
● May have intraepidermal vesicles, exocytosis, papillary dermal edema or perivascular lymphocytic infiltrates in upper dermis, also numerous eosinophils

Micro images

Various images

Psoriasiform epidermal hyperplasia with spongiosis and parakeratosis; superficial perivascular infiltrate of lymphocytes and eosinophils with exocytosis

End of Skin-nontumor / Clinical Dermatology > Other dermatoses > Allergic Contact Dermatitis

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