<s>[INST] My  4 month old baby has a purple/reddish lump on her mid back that seems to be getting larger. Her doctor said it could be a platelet issue, I cant remember the term she used, and that we would watch it closely. Do you know what the doctor is talking about and should I get another opinion?? [/INST] Hi, thanks for writing to Chat Doctor and sharing your babies health concerns with us! Well, If I were your treating Doctor for this case of the purple/reddish lump on the mid-back of baby, I would think of few possibilities :1. A purpuric spot/hematoma/ecchymosis due to low platelet count or ITP/Thrombocytopenia2. A congenital mole or nevus3. An abscess/boil/infected cyst etc think your clinician is thinking the same way as me... Hope this answers your question. If you have additional questions or follow-up questions then please do not hesitate in writing to us. I will be happy to answer your questions. Wishing your baby good health. </s>