IT IS INCLUDED IN SOME SKIN PREPARATIONS FOR MUSCULO-SKELETAL DISORDERS. INTRADERMAL INJ OF HISTAMINE TYPICALLY PRODUCES TRIPPLE REACTION OF ERYTHEMA, FLARE AND WHEAL.THIS IS UTILISED AS CONTROL RESPONSE IN TESTING FOR HYPERSENSTIVITY ALSO , SINCE IT IS MEDIATED IN PART BY AXON REFLEXES, IT HAS BEEN USED TO TEST THE INTEGRITY OF SENSORY NERVES FOR EXAMPLE IN LEPROSY. INHAILATION OF HISTAMINE CAUSES BRONCHOCONSTRICTION AND IS USED AS A TEST FOR BRONCHIAL REACTIVITY.