Do you give piriton at every blotch/ red mark/ rash??

[chlochlo]

just wondering when to just leave it and wait and see.

no, only if a clear allergic reaction, like hives.

do you give it at first sight like just one or two patches.

dd2 is allergic to egg so if she starts to get those swollen hives i give it to her straight away as i recognise them.
but if just a blotch/rash whatever then i wouldn't give it unless i had seen a doctor.

for example ds has known allergies sometimes resulting in anaphlatic reactions.
Yesturday whilst playing he came up in 4 patches of nettle rash type rash on his face (cause unknown) he can be like this several times a day sometimes Would you give piriton every time or give it chance to go.
TIA

If he has known allergies that are severe enough to cause anaphylaxis then I think I'd ask the doctor's advice about when to give Piriton rather than leave it to chance.