Two-year-old Sam Mccreadie was born with mastocytosis, which causes agonising blisters that can lead to his body going into anaphylactic shock.
A hug, touching a strawberry, or stepping into the cold is enough to trigger a severe skin reaction.
As a result, his mother, Jennifer, 26, has to carry a medical bag containing a syringe of adrenalin - called an Epi-pen - with her at all times and Sam wears a special T-shirt to warn others against giving him treats.
Mrs Mccreadie, from Invergordon, Ross-shire, said: "He has lots of triggers - heat, stress, certain foods, cleaning products, the cold - even snow or a cold wind touching his skin will set him off.
"We found at toddlers' group even food touching his hands would get into his skin and trigger an episode. We also have to be careful when we are play fighting with Sam, having a cuddle on the sofa or when he is in his buggy. Basically too much of anything can trigger an episode."
Sam's condition, which affects just one in half-a-million people, has left him with 60 permanent lesions on his head, face, arms, legs, back and waist.
Now Mrs Mccreadie and husband Peter, 32, have pledged to raise £10,000 for the UK Mastocytosis Support Group, which has helped them deal with their son's condition, in a bid to fund further research into the illness. The charity helped find the right drugs to help control Sam's condition.