The following statements regarding histamine are true, except:
Histamine characteristically causes dilation of the finer blood vessels and tends to constrict the larger blood vessels, it is used as a positive control injection during allergy skin testing. It can stimulate various nerve endings and in the dermis it evokes pain and sometimes itching. Contraction of bronchial smooth muscles is due to activation of H1 receptors and relaxation is due to activation of H2 receptors. Hence, blockade of H2 receptors can potentiate histamine-induced bronchospasm.
It can be used as a positive control injection during allergy skin testing
In the dermis, it evokes pain and sometimes itching
Bronchospasm is induced by histamine by  blockage of H2 receptors
It tends to dilate larger blood vessels