Pulsar pair-production theories imply that the plasma leaves the source already flowing relativistically. Such winds might also have relativistic injection temperatures. MHD models of relativistic pulsar winds were considered, and it was shown that in this case cold wind theories can be misleading.
On the other hand, due to synchrotron radiation losses, the temperature of collisionless, strongly magnetized, relativistic plasma quickly becomes anisotropic. In this case the plasma pressure is no longer a scalar and to describe the properties of stellar wind a hydrodynamical model of relativistic plasma with the anisotropic temperature distribution should be developed.