Patients may notice a small lump under their skin after a subcutaneous injection. This lump usually goes away on its own, but in some cases may persist for weeks or longer.

What causes a lump after a subcutaneous injection?

There is a certain element of trauma and inflammation after an injection, which may lead to the formation of a lump under the skin. The amount and intensity of the inflammation can be a result of many factors:

• Repeated injections at or near the same site
• The amount of medication injected
• The speed at which the injection is administered
• Needle size
• Reusing needles
• Allergic response

Are lumps harmful? How long do they last?

These lumps are typically not harmful and can persist for a few weeks to even several months.

What are signs / symptoms that a lump might be harmful?

• Fever
• Chills

Lumps under the skin should not be:

• Hot or warm to the touch
• Raised and red
• Painful
• Have pus drainage from the lump

It could be a sign of an infection if you experience any of the above. Please contact your PCP or Hone doctor for further evaluation and treatment.

If you are experiencing skin rash, itching, hives, trouble breathing or swallowing, swelling of the face, lips, tongue or throat, you should seek medical attention immediately as this may be a sign of an allergic reaction.

Is there a treatment for these lumps?

While there is no specific treatment for benign lumps, there are several things you can do to help prevent them or to minimize their frequency:

• Rotate injection sites each time - alternate between abdomen, upper outer gluteal region, and upper outer thigh with at least 3 finger widths apart
• Do not reuse needles - needles should be disposed of properly after an injection
• Clean the rubber vial top and injection site with an alcohol swab before drawing up medication and injecting
• Avoid pinching the skin at the site after injecting as this may increase the pressure inside the tissue
• If you're injecting over ½ mL, you may want to consider intramuscular (IM) injections instead
• Do not aspirate (pull back on the plunger) when injecting
• Inject very slowly - medication going through a small needle quickly can injure the tissue in which you are injecting
• Gently massage the area for several minutes after the injection
• Use a small muscle vibrator or shower pulsating water at the lump site several times per week