Poison ivy rash

This rash occurs following direct contact with a poison ivy plant and causes a painful, itchy skin rash which lasts for several weeks.

Poison ivy rash is a form of allergic contact dermatitis – an inflammation of the skin caused by an abnormal reaction from the immune system. It views a substance or allergen as a threat which it reacts to by releasing antibodies. These antibodies cause the skin to become itchy and inflamed as a result.

Poison ivy rash is not contagious.

Causes of poison ivy rash

Poison ivy is a common climbing plant which you often see up the sides of houses or other buildings. The leaves of this plant contain a substance called ‘urushiol’ which takes the form of a sticky, oily based resin.

If you brush up against this plant your skin will absorb urushiol which causes an allergic reaction. It only takes a small amount for this to happen.

A reaction occurs if you touch, brush against or handle objects which have been in contact with urushiol. This even applies to pets: urushiol sticks to their fur but doesn’t harm them in any way. But it transfers to you when you stroke or touch your pet in any way.

The thing to remember is that urushiol remains allergenic for a long period of time and we are talking years here. For example, you may own a jacket which has been in contact with urushiol without your knowledge. This substance remains on the jacket, even after several years and only needs you to handle this jacket to trigger a reaction.

Urushiol is also present in smoke from burning poison ivy and other similar plants such as sumac. It is possible to inhale urushiol as a result which then irritates your eyes, nose and throat.

Symptoms of poison ivy rash

A red, itchy, inflamed rash which forms blisters that may ooze pus. This rash appears 12 to 48 hours following initial contact and lasts for up to 2 months.

The extent of the rash depends upon how much urushiol is on your skin. The more urushiol on your skin the more severe the skin rash (and the symptoms).

New patches of rash may appear a few days after the first symptoms but this is due to the amount of urushiol in your skin.

Does scratching cause the rash to spread? No, but if you have any germs or bacteria on your fingers then this may lead to a secondary infection.

Diagnosing poison ivy rash

You do not need to see your GP unless complications develop. Poison ivy rash usually clears up without medical treatment but if you are concerned then ask your GP for advice.

Treatment for poison ivy rash

This is a condition you can treat at home. Apply calamine lotion to the rash or a cold flannel as this will soothe the inflammation and itching.

If you have a severe form of poison ivy rash or the rash has caused a large volume of blisters then your GP will prescribe a corticosteroid which is taken by mouth.

Complications of poison ivy rash

Poison ivy is a mild skin condition which disappears without any problems. But there are a small percentage of cases where complications arise. These include:

  • Fever
  • Skin rash spreads to the eyes, genitals or mouth
  • The blisters leak pus
  • The rash fails to clear after a few weeks

If you are experiencing a severe form of this rash then see your GP.

Can you prevent poison ivy rash? It is a good idea to avoid contact with poison ivy plants and wash your hands with soap and water if you have been in contact with poison ivy. Protect your skin with a barrier cream.