Why does my injection site itch?

It’s quite common to get a local itchy reaction to some medication injections, particularly when injecting subcutaneously. These are usually mild, can feel like a large mosquito bite, and resolve on their own within a few days. Some people are more prone to these reactions than others.

The itching is most likely contact dermatitis from Benzyl Alcohol (BA) or Benzyl Benzoate (BB) which are in steroid products as preservatives and solvents.

As you remove the needle, oil travels back up the injection site and comes into contact with skin layers, causing contact dermatitis.

These reactions may be helped by taking antihistamines, anti-inflammatories, using an icepack on the site and rotating injection sites.

Can you prevent the itching?

If you are sensitive to these products, you probably can’t totally prevent the itching, but you may be able to reduce it by:

  • Injecting slowly
  • Leaving the needle in for a few seconds after the injection while the oil is absorbed
  • Using the Z-Track injection technique
  • Finding a brand that has lower levels of BA and BB in their products

How do you tell the difference between this and an infection or more serious reaction?

Normal site reactions should be mild and disappear within a couple of days. You need to take them seriously when accompanied by:

  • Extreme or persistent pain at the site
  • Fever
  • Swelling or hardness at the site that doesn’t go away within a day or two
  • Redness that has distinct margins, and grows in size

You should call for an ambulance if you experience any of the following:

  • Hives (widespread itching)
  • Swelling of lips, tongue or face
  • Shortness of breath
  • Tightness in the chest

If you are ever unsure, talk to your GP, go to emergency, or chat to a nurse at your local needle exchange clinic.

You can find more information on injection techniques HERE

Videos showing how to do the Z-Track technique, and how to correctly find injection sites can be found HERE

Information on injection safety, techniques and FAQs can be found HERE