What can cause a water blister on my child's palm?

Thanks for the interesting question. It is difficult to tell for sure the cause without seeing the palms. Some commoner causes of yellowish or orangy palms include excessive intake of beta carotene found in foods like carrots and spinich or lycopene, found in tomatoes and beets. In fact, my son has yellowish palms from eating lots of carrots! By cutting down on these foods, the orange hue should resolve. Thyroid abnormalities and diabetes may also be possible causes. Contact with orange coloured dyes can also leave an orangu stain.

Thank you for your photo and question. I agree with Dr Colin Theng that you should bring your child to a doctor or dermatologist to determine the cause of the blister and treat it appropriately. The most common cause of such blisters seen in young children would be an insect bite reaction, although other causes such as infection, allergies or burns can certainly result in a similar appearance. The treatment would usually consist of letting the fluid out of the blister and treating with an appropriate cream.