Acute inflammatory reactions are associated with physical tissue injury and the injection of pigment, dyes, or metals into the skin. This reaction usually recedes without consequence within 2-3 weeks and is an expected adverse effect of the tattooing process.
Once any acute inflammatory changes have resolved, the most frequent reaction observed with tattoos is an allergic sensitivity to one of its pigments. Individuals may manifest sensitivity to a particular pigment in several ways. Histopathologic evaluation of involved skin may reveal a spongiotic, granulomatous, or lichenoid type of tattoo reaction. Allergic contact dermatitis from temporary henna tattoos has also been recognized, although this is technically not a tattoo but a painted-on skin decoration. The reaction is due to the brightener in the henna, which is often paraphenylenediamine, a known allergen.
Commonly, hypersensitivity reactions to a tattoo pigment result in contact dermatitis or photoallergic dermatitis. These conditions may manifest clinically as localized eczematous eruptions or, rarely, as an exfoliative dermatitis. Histopathologic findings include acanthosis, spongiosis, and a lymphocytic perivascular infiltrate.
Lichenoid hypersensitivity tattoo reactions are less common than eczematous reactions. Evidence exists that the lichenoid reaction is an expression of delayed hypersensitivity to a lymphocytic T-cell infiltrate, which may simulate the graft-vs-host response.
Delayed hypersensitivity to tattoo pigment may result in a pseudolymphomatous reaction. Lymphadenosis benigna cutis (pseudolymphoma) can develop after various foreign substance exposures, including insect bites, acupuncture, antigen injections, earrings, and tattoos.
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Cite this: Brett Sloan. Fast Five Quiz: Tattoos - Medscape - Sep 10, 2020.