Topical Diphenhydramine

[Aznfarmerboi]

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http://www.annals.org/cgi/content/full/128/11/931

Relief from Mosquito Bites

Cutaneous responses to mosquito bites range from common localized wheal-and-flare reactions to delayed bite papules, rare systemic Arthus-type reactions, and anaphylaxis [115-117]. Bite reactions are the result of sensitization to mosquito salivary antigens, which lead to the formation of specific IgE and IgG antibodies [118-121]. Immediate-type reactions are mediated by IgE and histamine, whereas cell-mediated immunity is responsible for the delayed reactions.

Several strategies exist for relieving the itch of mosquito bites. Topical corticosteroids can reduce the erythema, itching, and induration. Topical diphenhydramine and caine-containing derivatives should be avoided because of concerns about inducing allergic contact sensitivity. Oral antihistamines can be effective in reducing the symptoms of mosquito bites. Cetirizine was given prophylactically in a double-blind, placebo-controlled, 2-week, crossover trial to 18 persons who had previously had dramatic cutaneous reactions to mosquito bites [122]. Persons who received the active drug had a statistically significant 40% decrease in the size of the wheal response at 15 minutes and the size of the bite papule at 24 hours. The mean pruritus score, measured 0.25, 1, 12, and 24 hours after the mosquito had bitten, was 67% less than that of the untreated controls. These studies have not been done with astemizole, terfenadine, loratadine, or fexofenadine. In highly sensitized persons, prophylactic treatment with nonsedating antihistamines may safely reduce the cutaneous reactions to mosquito bites.

I am curious as if anybody has more information on allergic contact sensitivity relating to topical diphenhydramine. Any information would be greatly appreciated!

 

[type b pharmD]

http://www.annals.org/cgi/content/full/128/11/931

Relief from Mosquito Bites

Cutaneous responses to mosquito bites range from common localized wheal-and-flare reactions to delayed bite papules, rare systemic Arthus-type reactions, and anaphylaxis [115-117]. Bite reactions are the result of sensitization to mosquito salivary antigens, which lead to the formation of specific IgE and IgG antibodies [118-121]. Immediate-type reactions are mediated by IgE and histamine, whereas cell-mediated immunity is responsible for the delayed reactions.

Several strategies exist for relieving the itch of mosquito bites. Topical corticosteroids can reduce the erythema, itching, and induration. Topical diphenhydramine and caine-containing derivatives should be avoided because of concerns about inducing allergic contact sensitivity. Oral antihistamines can be effective in reducing the symptoms of mosquito bites. Cetirizine was given prophylactically in a double-blind, placebo-controlled, 2-week, crossover trial to 18 persons who had previously had dramatic cutaneous reactions to mosquito bites [122]. Persons who received the active drug had a statistically significant 40% decrease in the size of the wheal response at 15 minutes and the size of the bite papule at 24 hours. The mean pruritus score, measured 0.25, 1, 12, and 24 hours after the mosquito had bitten, was 67% less than that of the untreated controls. These studies have not been done with astemizole, terfenadine, loratadine, or fexofenadine. In highly sensitized persons, prophylactic treatment with nonsedating antihistamines may safely reduce the cutaneous reactions to mosquito bites.

I am curious as if anybody has more information on allergic contact sensitivity relating to topical diphenhydramine. Any information would be greatly appreciated!

did they wait for people to get bitten and then had them come in right away?? or did they lock the people in a room with mosquitos in order to do the test?