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Knot In Leg After Vaccine For Baby

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My son has a small knot in his leg, it showed up after his 4 month vaccines. It has been 2 weeks since he had them (vaccines) and the knot is still there. Why is this and is it common? Should I take him to the doctor?

Baby Help Line:

Lump After Vaccination – Normal?

The lump that your son still has on his leg is quite a common side effect of the diphtheria-acellular pertussis-tetanus vaccine (DtaP). It is due to a small inflammation caused by some of the injection material in the vaccine. It is not dangerous, nor painful and it can actually take even months to disappear.

The lump usually comes right after the shot, but it can also appear a few days later. As long as it doesn’t hurt or change in size or color, there is no need to worry. It is called a DtaP granuloma, by the way.

If your son seems to be bothered by it, or if you worry that it isn’t related to the vaccine, have his health-care provider look at it.

You can read about other side effects of vaccination here.

I hope this helps,

Find comments below.


Comments for “Knot In Leg After Vaccine For Baby”

Jun 02, 2013

lump and indention in upper thigh after shots

by: Anonymous


When my daughter got her 4 month shots her little legs lumped up really good she will now be 6 months old on 10/10 and still has a lump and a indention where one of her shots was placed.

Im getting a little worried

Thank you

Jun 02, 2013

A lump after the DtaP is normal
by: Paula (Baby Help Line)


As I wrote above, it can take a long time for the lump to disappear, months even. But if you are not completely sure that the lump is related to the vaccine or if it starts changing in anyway (unless diminishing), then let a doctor have a look at it.

Jul 13, 2013

4yr. old knots from shots
by: Chrissy

My daughter is 4yrs old and received the shots in her legs. Its been a week now. I’m worried because,she also has sickle cell anemia ss. These lumps are huge an warm. She’s also complaining about them hurting. I’ve been applying warmth packs and giving pain meds. What should I do?

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