My 6 year year old daughter has had 2 blister/wounds which appeared spontaneously 1 year apart from each other approx. (first in Nov 2022, 2nd in Dec 2023). The first was on her forearm which was quite nasty, got infected once it burst, took a long time to heal and left a nasty scar. It got investigated but it was a mystery and was put down to a one off and possibly a mysterious bite of some kind. Overall it took 3 months to heal. However she has a second one now on her knee, almost identical to the first in size/shape but this one has not got infected so far and although slow to heal, it isn't as bad as the first one. Photo attached of how this latest one started and at it's worst point recently - gap in photos is about 1 week. We have had blood tests and swabs etc and nothing obvious has been found. She is generally fit and well otherwise. But the Consultant Dermatologist she is under and others just can't diagnose it at the moment- the closest thing it could be we think is Mastocytosis but the symptoms just don't seem typical of that. Also, one of her blood tests for tryptase which she had last year (and may have provided more insight at the time) went missing. As a few months had passed since it occurred, it wasn't felt these needed repeating. We had the bloods re-done yesterday (traumatic!) which will take at least a couple of months to come back. Hopefully that will either tell us something or at least rule more things out. We think it still may be some kind of mast cell / autoimmune issue as this latest time she had her flu spray the day before which could have been coincidence but it's the only thing we have to go on at the moment as some kind of explanation. She hadn't had her flu spray before the 1st one. It's strange that it was almost exactly a year apart which makes me think it could also be something seasonal/viral given the time of year. Our priority is to manage this one to heal it well and have a better course of action if another occurs in the future. Following some research, it does appear if it is a mast cell condition, antihistamine is one advised approach when it appears. It is quite concerning this is the 2nd now and the recovery time is quite upsetting and disruptive for her with the regular dressing changes although she isn't really complaining. It is the worry of the scarring and others appearing in more prominent areas of her body which is really stressing me out now. We are now armed with antibiotics, creams, and antihistamine for possible future episodes to get on top of it straight away but the doctor has said it will unfortunately be a bit of trial and error to narrow it down to either an infection/viral issue or an autoimmune issue to determine long-term management and treatment if they are needed but we won't really know until we've tried each measure in turn if another appears, which obviously we hope it doesn't but I understand this approach. Apologies for the long post but just asking if anyone has experienced anything similar - we cannot find anything at all online that matches our experience and the fact the experts are stumped too, we are wracking our brains a bit now. Nothing out of the ordinary led up to either episode other than what I've already mentioned (i.e. we weren't rolling round in the forest and we haven't got a pet spider!). Thanks for sharing if you have experienced anything similar and can offer any advice.