CLL Support Association

Antihistamines and CLL?

I have been traveling for some time now and last week I caught a severe cold, the codral cold and flu tablets you normally get in Australia are not available here in Switzerland so I was reminded that antihistamines can really help, so I got these (1 a day type ) and the cold symptoms really cleared up within the day of taking them, but after taking them for 2 days I got a huge disgusting cold sore on my lip in a place I had never had one before, i am wondering having CLL can antihistamines give you a cold sore as they might lower my immunity?... Appreciate your thoughts!...

2 Replies

No they won't lower your immunity. My CLL doc has me on Zyrtec. Of course, you should do what I did and check with you Hematlogist first. What do I know? Just kidding. I hope you feel better soon and don't kiss anyone 💋



Hello Heidiypi,

I'm not a doctor, but I wouldn't have thought that antihistamines would cause cold sores... Sounds like you've had cold sores in the past, and it could be that because your immune system is now affected by CLL, any virus (such as those that cause cold sores) is likely to hit you a bit harder than before, as the CLL "progresses".

If it doesn't get better soon, it would be good to ask a doctor about it. There might be some ointment that would help. You say it's very large and in an unusual place, so it might be best to check that it really is a cold sore and nothing else.

I was prescribed antihistamines (Cetirizine 10 mg once daily) a couple of months ago, due to some nasty skin rashes I was getting in reaction to antibiotics. I didn't have any problems with it, and I'm still taking them. My CLL has actually stabilised during that time. (I think it was stabilising anyway, so I don't think the antihistamines were involved in that.) However, antihistamines can sometimes reduce inflammation, and inflammation can aggravate CLL, so I would think it more likely that antihistamines would have a helpful affect on CLL, rather than the opposite...

Best wishes,


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