respiratory distress; Urticaria; severe abdominal pain; emesis; lethargy; This case was reported in a literature article and described the occurrence of respiratory distress in a 5-year-old male patient who received DTPa (Diphtheria tetanus acellular pertussis) for prophylaxis.   The patient's past medical history included vomiting (Patient had history of emesis and blood in stools associated with cow's milk ingestion) and blood in stool (Patient had history of emesis and blood in stools associated with cow's milk ingestion). Concurrent medical conditions included milk allergy (presence of immunoglobulin E (IgE) to milk (sIgE 24.30 kIUA/L, age 18 months)). Concomitant products included DTPa (Diphtheria tetanus acellular pertussis), DTPa (Diphtheria tetanus acellular pertussis), DTPa (Diphtheria tetanus acellular pertussis), DTPa (Diphtheria tetanus acellular pertussis), MMR (MMR vaccine) and MMR (MMR vaccine).   On an unknown date, the patient received the 5th dose of Diphtheria tetanus acellular pertussis. On an unknown date, less than an hour after receiving Diphtheria tetanus acellular pertussis, the patient experienced respiratory distress (serious criteria GSK medically significant), urticaria, abdominal pain, vomiting and lethargy. The patient was treated with epinephrine. On an unknown date, the outcome of the respiratory distress, urticaria, abdominal pain, vomiting and lethargy were recovered/resolved.   The reporter considered the respiratory distress, urticaria, abdominal pain, vomiting and lethargy to be related to Diphtheria tetanus acellular pertussis.  This case was reported in a literature article and described the occurrence of urticaria, severe abdominal pain, emesis, respiratory distress, and lethargy in 5-years-old male patient who was vaccinated with unspecified diphtheria, tetanus and pertussis (DTaP) vaccine (manufacturer unknown) for prophylaxis.  The patient had a history of emesis and blood in stools associated with cow's milk ingestion and the presence of immunoglobulin E (IgE) to milk (sIgE 24.30 kIUA/L, age 18 months). No information on patient's family history or concomitant medication or concurrent condition was provided. On an unspecified date, at the age of 5 years, the patient received 5th dose of unspecified DTaP vaccine (administration route and site unspecified; batch number not provided) with measles, mumps, and rubella (MMR) vaccine together (administration route and site unspecified; dosages unknown; batch number not provided).  On an unspecified date, within 60 minutes of vaccination, the patient developed urticaria, severe abdominal pain, emesis, respiratory distress, and lethargy. Symptoms resolved within minutes after administration of intramuscular epinephrine. The patient developed symptoms, which were consistent with IgE-mediated reactions. It was reported that the patient previously tolerated the MMR vaccination and four doses of DTaP. In 2017, at the age of 11 years, he presented for allergy evaluation. Skin prick test (SPT) results were as follows (wheal/flare): saline 0 mm/0 mm; histamine 5 mm/ 0 mm; DTaP(1:10 dilution): 0 mm/0 mm; Tdap (1:10 dilution) :0 mm/0 mm; full strength DTaP: 0 mm/ 0 mm; DT full strength: Not done.  Intradermal testing (IDT) results were: saline: 0 mm/0 mm; DTaP (1:100 dilution): 8mm/ flare not recorded; Tdap (1:100 dilution): 0 mm/0 mm; DT (full strength): Not done. He subsequently tolerated a single dose of Tdap vaccine without adverse reaction.  The author considered the event of urticaria, severe abdominal pain, emesis, respiratory distress, and lethargy related to the unspecified DTaP vaccine.  The authors stated, "There were reports of anaphylaxis to natural rubber latex within the syringe or stopper of some vaccines. Some DTaP and Tdap vaccine packaging contains natural rubber latex. We were unable to obtain the name of the manufacturer and lot number of the original vaccines administered to the three patients. All three patients previously tolerated either DT or DTaP prior to their reaction, suggesting some degree of sensitization to the vaccines could had occurred prior to the reactions prompting future testing and challenge. Skin tests were difficult to interpret due to lack of complete results recording and uneven responses to positive and negative controls, but might had shown some reactivity to DTaP in patients 2 and 3. If so, the reactivity to DTaP and not Tdap might had been due to the larger amount of diphtheria and pertussis antigen in the former. DTaP and Tdap contain trace amounts of residual casein in the medium raising concern for potential allergic reaction including anaphylaxis. This series demonstrates the negative predictive value of SPT and IDT in allowing for subsequent Tdap challenge for patients with previous adverse reaction to DT or DTaP. The amount of time that elapsed between doses or why patients 1 and 2 were administered Tdap in graded doses versus a single dose for patient 3 was not documented. We speculate this variability might had been related to clinical judgement during the procedures. Reactions had been described to DTaP and DT, but there are limited case reports of subsequent skin testing followed by successful Tdap administration. Following the Practice Parameter Update protocol, we were able to safely perform skin testing and Tdap immunization for three patients with IgE-mediated reactions to DTaP or DT".  This is 1 of the 3 valid cases reported in the same literature article.      Lab Comments: In 2017, at the age of 11 years, he presented for allergy evaluation. Skin prick test (SPT) results were as follows (wheal/flare): saline 0 mm/0 mm; histamine 5 mm/ 0 mm; DTaP(1:10 dilution): 0 mm/0 mm; Tdap (1:10 dilution) :0 mm/0 mm; full strength DTaP: 0 mm/ 0 mm; DT full strength: Not done. Intradermal testing (IDT) results were: saline: 0 mm/0 mm; DTaP (1:100 dilution): 8mm/ flare not recorded; Tdap (1:100 dilution): 0 mm/0 mm; DT (full strength): Not done. He subsequently tolerated a single dose of Tdap vaccine without adverse reaction.