Table 1.

Effect of selective histamine receptor antagonists on neurogenic inflammation

	Histamine receptor subtype
Effect	H1R	H2R	H3R	H4R
Pain	↓	↓	↓	↓
Hyperalgesiaa	↓	↓	↓	↓
Allodynia	?	?	↓	?
Itch	↓	↔	↑	↓
Sneezing response	↓b	?	?	?

^aThe differential involvement of histamine receptor subtypes has been demonstrated in different experimental models.

^bOnly at high doses.