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Posted On : 09 Dec 2009

can i do a skin sensitivity test with benzatahane pencilin before injecting it. or the sensitivity test should be done by benzyl pencillin. thanks dr.ishtiaq

Expert Answer :

Answer Discussion :

M

mangalmoorti bhalerao

0

sensitivity test should be done with benzathine penicillin .

15 years ago

A

ashraf deghedy

0

yes i can

15 years ago

S

Shantilal Vora

0

sensitivity test to be done with benzathane peniilline

15 years ago

R

Rajesh Ranjan

0

done with benzathine penicillin

15 years ago

A

ANITA SINGH

0

sensitivity should be done by benzathine penicilline

15 years ago

Answer 1

For penicillin skin testing the reagents used are:
Benzylpenicilloyl-polylysine {major pre-Pen G x 10-5 M}
Benzylpenicillin {10-2 M or 6000U, mL}
If available
Benzylpenicilacloic acid {10-2 M}
Benzylpenilloic Acid {10-2 M}
Positive control {histamin1e.0 mg, mL}
Negative control {buffered saline solution}

Dilute the antigen 100 s fold for preliminary testing if there has been an immediate generalized reaction within the past
year.

Procedure
Epicutaneous {scratch or prick} test with a drop of each reagent: examine for 15 minutes` if there is no significant
wheal {4 mm or greater} proceed to intra-dermal test.

Intradermal test: inject 0.02 mL intradermally with a 27-gauge short-bevelled needle` observe for 20 minutes

Interpretation
Conclusions are only possible if the negative control is negative and the positive control is positive.
Positive test: a wheal greater than 4 mm in mean diameter to any penicillin reagent` erythema must be present
Negative test: the wheals on the penicillin reagents are equivalent to the negative control
Inderterminate: all other results

Skin testing should be restricted to patients with a history of prior penicillin allergy for whom a penicillin or other B-lactam antibiotic is the indicated drug of choice and there is no suitable alternative antibiotic. There is no need to do skin testing prior to the treatment of patients without a history of penicillin allergy even if the drug is to be admin istered parenterally. If only benzylpenicillin is used for testing, a negative skin test does not ensure absence of an immediate reaction. Hence, in a patient with a good history of prior penicillin allergy, a test dose still needs to be given even if the skin test {using only benzylpenicillin} is negative.

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