Injection site rash

TheyCallMeStacey · 2025-08-12T11:54:18+00:00

I’m week 16 of mounjaro and have had an injection site reaction for probably the last 6/7 weeks. It comes up as a red itchy hot patch which lasts for about four days. It hasn’t got any worse over the weeks and is very manageable but just wondering if anyone has anything similar? I have tried ensuring the medication is room temperature, moving sites, injecting into fat etc. I have used aloe vera gel which is really helpful.

GiveMeWordGames · 12/08/2025 12:59

I've had the same thing since about the second month (now five months in). I've tried similar measures to you which made no difference but recently it's improved of its own accord. It certainly never got bad enough to be anything more than annoying. It's quite common I think.

AsteriaBuffy · 12/08/2025 13:12

I had a reaction on my very first jab, a hot red slightly itchy patch about 2 inches x 1 inch on my thigh. Also a bit of bleeding. Took about 3 days to fade completely. I wondered if had anything to do with the wipe but prob not. As it was my first jab I was very nervous and managed to slightly bend the needle and forgot to count to 5 after the fluid went in so that may not have helped!

Second jab I did on a roll of tummy flab and the reaction wasn't nearly as bad, did leave a small bruise though. Will see how the third goes.

watchingplanesicantafford · 12/08/2025 13:12

I have this every time since about month two. Google says it's fairly common and fine as long as you don't have any allergic reaction type symptoms. I find calamine lotion really helpful.

HappyWineDay · 12/08/2025 13:24

A few people have reported sensitivity to the wipes rather than the local effect of the injection. It's worth noting that according to the instructions, the wipes are just for the rubber seal on the pen, they're not for wiping your skin before injecting.

Janie934 · 12/08/2025 13:48

I started getting a red itchy patch around the injection site about 4 months in. I started taking a daily antihistamine tablet and used hydrocortisone and antihistamine creams to help (and sometimes an ice cube wrapped in kitchen paper). Ive now been on the jabs for a year and the reactions seem to have stopped.

spoonbillstretford · 12/08/2025 14:19

I take Piriton and have this great antihistamine gel called Fenistil.

AsteriaBuffy · 12/08/2025 14:36

HappyWineDay · 12/08/2025 13:24

A few people have reported sensitivity to the wipes rather than the local effect of the injection. It's worth noting that according to the instructions, the wipes are just for the rubber seal on the pen, they're not for wiping your skin before injecting.

That's interesting, I could have sworn it said to clean your skin with the wipe but you're right, it doesn't. Maybe that was it that caused the red patch then, I only wiped a tiny area the second time in case it was the wipe and there was much less reaction.

watchingplanesicantafford · 12/08/2025 15:46

I've never cleaned my skin with the wipe and still get them. I think it's something to do with creating antibodies to the mounjaro itself. It doesn't appear to affect the effectiveness

Original poster

TheyCallMeStacey · 12/08/2025 16:47

I’ve never used the wipes on my skin either and I can’t take antihistamines unfortunately. I’m hoping it lessens over time.

OP posts:

AsteriaBuffy · 13/08/2025 12:54

ok scientific expt today (jab day) -

wiped another area of skin with the wipe
didn't wipe the injection site.

No reaction at all where I'd used the wipe, so prob nothing to do with that (unless jabbing some wipe residue into the skin had an effect I suppose).

Also not much reaction on jab site this time, just small red dot, nothing like the big welt that happened the first time. So maybe it was some sort of immune reaction that time, which hopefully isn't too anything too alarming.

WeAllHaveWings · 13/08/2025 13:34

Started with me when I changed supplier, after a bit of trial and error with needle lengths, pen temperature, I worked out it was the new suppliers pen needles I was reacting too (BD Viva), probably the propriety lubricant they use. Switched back to previous suppliers brand of pen needles (Novofine) and not had a reaction since.

Original poster

TheyCallMeStacey · 13/08/2025 14:47

WeAllHaveWings · 13/08/2025 13:34

Started with me when I changed supplier, after a bit of trial and error with needle lengths, pen temperature, I worked out it was the new suppliers pen needles I was reacting too (BD Viva), probably the propriety lubricant they use. Switched back to previous suppliers brand of pen needles (Novofine) and not had a reaction since.

That’s interesting! I’m wondering if it lines up with changing from Medexpress to Pharmacy 2U. I’ll do some research.

OP posts:

Original poster

TheyCallMeStacey · 13/08/2025 14:48

AsteriaBuffy · 13/08/2025 12:54

ok scientific expt today (jab day) -

wiped another area of skin with the wipe
didn't wipe the injection site.

No reaction at all where I'd used the wipe, so prob nothing to do with that (unless jabbing some wipe residue into the skin had an effect I suppose).

Also not much reaction on jab site this time, just small red dot, nothing like the big welt that happened the first time. So maybe it was some sort of immune reaction that time, which hopefully isn't too anything too alarming.

Love the experiment! I have a feeling it’s a histamine type reaction which is not showing any signs of disappearing week to week for me.

OP posts:

LifeOfAShowGirl · 13/08/2025 14:49

I get this if I don’t let the alcohol dry fully on my skin before jabbing

AlicesMum2025 · 13/08/2025 16:21

I get this. It started when I went up to 3.75mg and lasts for 4-5 days. I was jabbing in my belly and would get big bruises too. I changed to my thigh the past two weeks and still the red, itchy lump (about 2" wide) but no bruising. I don't wipe the skin before or after. It happens if I use a syringe and needle too.

Fortunately this is pretty much my only side effect so I'm happy to put up with it. I'm going to try insect bite cream on it this week to see if that helps.

Hopefully my body will eventually get used to MJ though.

toadinthebucket · 13/08/2025 18:27

I get this if after priming the needle there is any of the medication on it. It's the medication coming into contact with my outer layer of skin. When my nurse DP injects me, this never happens, only when I do it myself!

AsteriaBuffy · 13/08/2025 23:33

toadinthebucket · 13/08/2025 18:27

I get this if after priming the needle there is any of the medication on it. It's the medication coming into contact with my outer layer of skin. When my nurse DP injects me, this never happens, only when I do it myself!

Oh that makes sense for my reaction then, lots of the jab liquid and a bit of blood seemed to drain back out as I was so cack handed, and I guess when I wiped it, it went on my skin. Today (3rd jab) I was much more proficient with no drips and no reaction.

watchingplanesicantafford · 14/08/2025 06:49

toadinthebucket · 13/08/2025 18:27

I get this if after priming the needle there is any of the medication on it. It's the medication coming into contact with my outer layer of skin. When my nurse DP injects me, this never happens, only when I do it myself!

Interesting. How do you prime it without there being drips left on?

toadinthebucket · 14/08/2025 08:09

watchingplanesicantafford · 14/08/2025 06:49

Interesting. How do you prime it without there being drips left on?

Show quote history

20 years of practice? I assume it's the injection technique but I don't actually know. I just know there's a difference between him doing it and me. I always bruise myself too!

SecretSquirrel703 · 18/08/2025 09:00

toadinthebucket · 13/08/2025 18:27

I get this if after priming the needle there is any of the medication on it. It's the medication coming into contact with my outer layer of skin. When my nurse DP injects me, this never happens, only when I do it myself!

Thank you! Super careful with my latest injection, no priming drops left on needle, only a very slight reaction which has now gone after 24 hours.
Bit if a relief after a very irritating rash for me previous 2 jabs & I didn't understand what had changed from the previous 11 weeks with no reaction 🤷‍♀️

AlicesMum2025 · 18/08/2025 16:21

Me too! I was just thinking to myself that I'm not scratching this week. It has to be because I was really careful to prime just enough so that there was a bead on top of the needle, not dribbling down the side. What a relief. 🤞 for the same again this week.

Thank you @toadinthebucket for the tip

watchingplanesicantafford · 18/08/2025 19:14

And me! I can't believe you solved it for us. The itching was driving me mad.

toadinthebucket · 19/08/2025 09:26

watchingplanesicantafford · 18/08/2025 19:14

And me! I can't believe you solved it for us. The itching was driving me mad.

I'm so chuffed that it helped!

Fluffypiece · 19/08/2025 11:40

I’ve had an injection site reaction for the first time today - immediately felt super lightheaded - subsiding a bit now but feel have a big headache / compression in my head . Took an antihistamine and have contacted my supplier but feel quite peculiar

AsteriaBuffy · 19/08/2025 11:48

Fluffypiece · 19/08/2025 11:40

I’ve had an injection site reaction for the first time today - immediately felt super lightheaded - subsiding a bit now but feel have a big headache / compression in my head . Took an antihistamine and have contacted my supplier but feel quite peculiar

Did you get any of the jab fluid on your skin? If you have a read below that seems to be a common factor in itchy reaction.

Good that you have contacted your provider :) hopefully just a bit of a panicky reaction causing the other symptoms, I felt weird after the rash happened to me but think it was just jitters. All fine though, the rash took a couple of days to fade.