A woman went to a beauty salon to use hyaluronic acid to hydrate her skin.Before injection，the worker smeared lidocaine and procaine mixture on her face for topical anesthesia.Just for a few minutes, her face turned red and were full of red macules and papules on her forehead and bilateral of ala nasi like manifestation of SLE.
The next day she went to see me and I gave the diagnosis of acute allergic contact dermatitis.
As we all know,allergic contact dermatitis is a type of Type IV hypersensitivity reaction,then why the onset was so fast like Type I? I was confused about that.
I think definition of type I more acceptable. Once a time I had a patient during urethral catheterisation, with local lubricant inside lidocain, in a few second laringeal spasm has occured
No doubt, this was type I allergic reaction, immediate hypersensitivity. Drugs could induce any type of allergic reaction.
In my opinion it is Type I allergic reaction, in this case lidocain was not injected but sprayed in the skin, "mimicking" a IV Type( contact dermatitis)..
An erythematous rash developed within a few minutes after a topical preparation could be either allergic contact dermatitis (type IV HSR) or contact urticaria (usually type I HSR)! To differentiate between these two possibilities is according to the type of rash whether eczematous (allergic contact dermatitis) or wealing (contact urticaria). Topical anesthetics of “caine“ group are well known topical inducers of allergic contact dermatitis. Lastly, allergic contact dermatitis usually develops within 48-72 hours after exposure to the culprit (elicitation phase), however, this is the usual scenario for first reaction. In subsequent reactions in “already sensitized individual“ the elicitation phase might be shortened and occasionally to a very short period! To confirm the diagnosis, PATCH TESTING can help.
The immediate reaction from topical aesthetics lidocaine & prilocaine may be either contact urticaria or a typical type 4 allergic reaction. If it's a type 4 reaction she must have been previously sensitised thus the quick reaction on this current exposure. I agree, patch testing must be done. It should be done at least 2 weeks from her last medications that controlled her allergic symptoms. To confirm contact urticaria, reactions must be observed within an hour of application of patch test. To confirm the type 4 reaction, the usual 48-hour, then 72 or 96 reading is performed.
Development of erythematous rash within a few minutes after first application of topical anesthetics may be due to irritant contact dermatitis.
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