RT Book, Section
A1 Chin-Hong, Peter V.
A1 Guglielmo, B. Joseph
A2 Papadakis, Maxine A.
A2 McPhee, Stephen J.
A2 Rabow, Michael W.
SR Print(0)
ID 1166175365
T1 Hypersensitivity
T2 Current Medical Diagnosis and Treatment 2020
YR 2020
FD 2020
PB McGraw-Hill Education
PP New York, NY
SN 9781260455281
LK accessmedicine.mhmedical.com/content.aspx?aid=1166175365
RD 2020/06/03
AB All  penicillins  are  cross-sensitizing  and  cross-reacting.  Skin  tests  using  penicilloyl-polylysine  and  undegraded  penicillin  can  identify  most  individuals  with  IgE-mediated  reactions  (hives,  bronchospasm).  In  those  patients  with  positive  reaction  to  skin  tests,  the  incidence  of  subsequent  immediate  severe  reactions  associated  with  penicillin  administration  is  high.  A  history  of  a  penicillin  reaction  in  the  past  is  often  not  reliable.  Only  a  small  proportion  (less  than  5%)  of  patients  with  a  stated  history  of  penicillin  allergy  experience  an  adverse  reaction  when  challenged  with  the  medication.  The  decision  to  administer  penicillin  or  related  medications  (other  beta-lactams)  to  patients  with  an  allergic  history  depends  on  the  severity  of  the  reported  reaction,  the  severity  of  the  infection  being  treated,  and  the  availability  of  alternative  medications.  For  patients  with  a  history  of  severe  reaction  (anaphylaxis),  alternative  medications  should  be  used.  In  the  rare  situations  when  there  is  a  strong  indication  for  using  penicillin  (eg,  syphilis  in  pregnancy)  in  allergic  patients,  desensitization  can  be  performed.  If  the  reaction  is  mild  (nonurticarial  rash),  the  patient  may  be  rechallenged  with  penicillin  or  may  be  given  another  beta-lactam  antibiotic.