Does your child have a lump or knot in their leg after getting a vaccine?
Is that a normal reaction?
Why Does My Child Have a Knot in Their Leg After Their Vaccine?
Developing a lump or knot in their leg after getting a vaccine is a common and very normal vaccine reaction.
It is well known that most vaccines will cause local reactions, with pain, tenderness, swelling, and tenderness where it was injected. Local reactions that are typically mild and go away with no or minimal interventions.
And then, in addition to these local reactions, some kids develop lumps or knots at the injection site.
These knots are usually painless and go away in a few days or weeks.
If the knot is bothersome, you can apply a warm compress to the injection site a few times a day.
Persistent Vaccination Nodules
What about a lump or knot that doesn’t go away in a few days or weeks?
“Granulomas are a local formation of specific cells including macrophages and lymphocytes, revealing a chronic inflammatory reaction against an inciting agent. The etiology of vaccination granulomas has been described as an inflammatory response incited by the injection of a vaccine, particularly those which are aluminum adsorbed.”
The Evaluation of Palpable Thigh Nodularity in Vaccination-age Children – Differentiating Vaccination Granulomas from Other Causes
In this case, the knot might have developed into a granuloma.
Why do some kids develop these knots?
“Rarely, delayed-type hypersensitivity to a vaccine
Adverse reactions to vaccines practice parameter 2012 update
constituent can cause an injection-site nodule, but this is not a
contraindication to subsequent vaccination.”
It could be a delayed-type hypersensitivity to a vaccine constituent (usually aluminum or neomycin), especially if the shot wasn’t injected deep enough into the muscle and some leaked into the subcutaneous space under the skin.
“Vaccine-induced itching granulomas caused by an aluminium-adsorbed acellular pertussis toxoid vaccine seem to disappear over time. Future vaccinations with aluminium-adsorbed vaccines can be performed with little risk for new itching nodules later in life.”
Long-term clinical course and prognosis of vaccine-related persistent itching nodules (1997–2019): An observational study
These knots, granulomas, or nodules eventually go away, are not usually a sign of any kind of systemic allergy or injury, and are not a reason to skip or delay your child’s vaccines.
More on Vaccine Side Effects
- Why Did My Child Get a Fever After Their MMR Vaccine?
- DTaP Vaccine Reactions – Is This Normal?
- How Often Do Severe Events Occur After Vaccines?
- How Long Do Side Effects of Immunizations Last?
- Is This a Horrible Vaccine Reaction?
- Injection site nodules
- Treatment of local injection reactions
- Adverse reactions to vaccines practice parameter 2012 update
- The Evaluation of Palpable Thigh Nodularity in Vaccination-age Children – Differentiating Vaccination Granulomas from Other Causes
- Long-term clinical course and prognosis of vaccine-related persistent itching nodules (1997–2019): An observational study
- Sixty-four children with persistent itching nodules and contact allergy to aluminium after vaccination with aluminium-adsorbed vaccines-prognosis and outcome after booster vaccination
- Immunization Reactions
- After your child is immunised
- What is normal after vaccination?
- Aluminum-based vaccine adjuvants: much ado about nothing
- Posts Raise Unfounded Concerns About Aluminum in Vaccines
- The level of aluminum in childhood vaccines is safe, even for babies