Heat rash and Hives

Heat rash noun - Obstruction of the sweat ducts during high heat and humidity.

Hives and heat rash are semantically related. In some cases you can use "Hives" instead a noun phrase "Heat rash".

Hives noun - An itchy skin eruption characterized by weals with pale interiors and well-defined red margins; usually the result of an allergic response to insect bites or food or drugs.

Heat rash and hives are semantically related. You can use "Heat rash" instead a noun "Hives".