Anti-allergic reactions

prior to  24 hours of  testing the patient should not have taken any anti-allergic  drugs.
Pharmacological actions of the agents interfere with skin tests response

Allergic skin testing

Systemic  reactions
-  flushing, dizziness, headache, bronchial constriction, urticaria, asthma,
marked hypertension or hypotension, abdominal  cramps, vomiting, metallic taste,
or local genealized manifestations

Do not inject histamine into individuals  with hypotension, severe hypertension, or severe cardiac , pulmonary, or renal disease

Special Precautions/Warnings-

Intercutaneous testing- use caution in intercutaneous testing to avoid injection into a venule
or capillary.

Bronchial disease - smal doses may precipitate asthma in patients with bronchial disease

Hypersensitivity - epinephrine injection 1;1000 and injectable antihistamine should be available for immediate  use in the event of severe response

Pregnancy -  use during pregnancy only if potential benefit justifies the potential risk to the fetus.

Lactation- wait at least 2 hours following exposure to histamine before breast feeding

Children- safety and efficacy in children  < 6 years of age have not been established.

Indication-

Allergic skin testing

Dosage - 
use histamine base 0.1mg/ml or histamine phosphate 0.275mg/ml or 0.01mg/ml to give
a positive reaction

Storage- refrigerate vials from light

Pregnancy - 
Use during pregnancy only if potential benefit justifies the potential risk to the fetus.

Lactation-
Wait at least 2 hours following exposure to histamine before breast feeding

Children-
Safety and efficacy in children  < 6 years of age have not been established.