Hi,

What a dreadfully scary time you have had! It must have been awful for you. It sounds though, at the end of the day the paediatrician didn't really have an explanation for the bruising.
Vitamin K is a vitamin (like Vit D) that nature didn't really intend for us to get through food. It is synthesised by bacteria in the gut. Ever though of why the vagina is so close to the anus? And why babies come out facing mum's bum? They get a good mouthful of bacteria which is great for their immune system and helps them to begin to make their own vit K. I wonder if you or your baby has had large doses of antibiotics - something which has killed off his gut flora, and compromised his ability to make his own vit K.
There are some food sources of vit K - but they are not easily available to the baby's body. Green vegies - spinach, kale, brussell sprouts etc are highest in vit K - but you would have to have a lot of it to get your daily requirements of vit K. Usually babies are started on rice cereal, fruit and vegies - especially at this age when their digestive system is not well developed.
We don't know what is causing the high prevalence of allergies in our society. There is much speculation - and we are all grasping in the dark. The allergists Association expound one theory. It hasn't been incorporated into Australian Health policy - nor is it likely to be. They argue that allergies have risen steeply in the last 10 years - the same period of time when the National Health and Medical Research Coucil has recommended introducing solids at 6 mnths. The flaw with this is that almost every Austalian child is exposed to foreign proteins in food - namely cows milk protein in formula. Many experts believe as few as 1% of babies are exclusively breastfed in line with WHO policies. There has been a very poor uptake, even, of the exclusive breastfeeding to 6 months (the ubiquitous use of formula aside!)
Back to the Vit K issue. The logical solution if his Vit K levels are low is to give supplements now. You can do this via injection or drops. Ask your dr to prescribe this. (Vit K levels could presumably be tested - your post doesn't say that his vit k levels WERE found to be low)
It would be good to get to the bottom of what IS causing this. It's your right to ask for a second opinion from another paediatrician if you feel that your questions have not been adequately answered
Hope this helps