A nettle agent or urticant is a variety of chemical warfare agent that produces corrosive skin and tissue injury upon contact, resulting in erythema

Erythema

Erythema is redness of the skin, caused by hyperemia of the capillaries in the lower layers of the skin. It occurs with any skin injury, infection, or inflammation...

, urticaria

Urticaria

Urticaria is a kind of skin rash notable for pale red, raised, itchy bumps. Hives is frequently caused by allergic reactions; however, there are many non-allergic causes...

, intense itch

Itch

Itch is a sensation that causes the desire or reflex to scratch. Itch has resisted many attempts to classify it as any one type of sensory experience. Modern science has shown that itch has many similarities to pain, and while both are unpleasant sensory experiences, their behavioral response...

ing and a hive

Hive

A hive may refer to a beehive, an enclosed structure in which some honey bee species live and raise their young.Hive may also refer to:-Arts:* The Hives, a Swedish rock band* Hive , a DJ and producer in the drum and bass music genre...

-like rash.

Most nettle agents, such as the best known and studied nettle agent, phosgene oxime

Phosgene oxime

Phosgene oxime, or CX, is an organic compound with the formula Cl2CNOH. It is a potent chemical weapon, specifically a nettle agent. The compound itself is a colorless solid, but impure samples are often yellowish liquids...

, are often grouped with the vesicant (blister agent) chemical agents. However, because nettle agents do not cause blister

Blister

A blister is a small pocket of fluid within the upper layers of the skin, typically caused by forceful rubbing , burning, freezing, chemical exposure or infection. Most blisters are filled with a clear fluid called serum or plasma...

s, they are not true vesicants.