Nettle rash and Skin rash

Nettle rash 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.

Skin rash and nettle rash are semantically related. In some cases you can use "Skin rash" instead a noun phrase "Nettle rash".

Skin rash noun - Any red eruption of the skin.

Nettle rash and skin rash are semantically related. Sometimes you can replace phrase "Nettle rash" with "Skin rash", this phrases are similar.