I don't know if I have NF

A couple years ago I noticed that I had freckles in my right armpit and I thought it was cool because no one else I knew had them. I've just now thought to look something up on the matter and after typing in armpit freckles into Google, every single page was about Neurofibromatosis. I already have Hoshimodo's Hypothyroidism and anemia, and so I don't want to bring up the topic of my having another health issue until I have a pretty accurate account of reasons why I would have NF. I don't have any cafe-au-lait spots that I know of which makes me seriously doubt that I have it because all of the other sites said that almost everyone with NF has at least 6 cafe spots. Please help me to determine whether I could really have NF so that I can go to the doctor and run tests. Thanks.

[Christopher R Newey, DO]

Thanks for using the forum. I am happy to address your questions, and my answer will be based on the information you provided here. Please make sure you recognize that this forum is for educational purposes only, and it does not substitute for a formal office visit with a doctor.

Without the ability to examine and obtain a history, I can not tell you what the exact cause of the symptoms is. However I will try to provide you with some useful information.

Neurofibromatosis is an autosomal dominant disorder (which is the mode of inheritance). To make the diagnosis, a patient needs to have six or more café au lait macules (which iff you are an adult need to be greater than 1.5cm), two or more neurofibromas (which may present as lumps that can be felt under the skin), and another finding such as axillary freckling as you describe.

However, you will need to have your axillar (armpit) examined to differentiate from acanthosis nigrans which is thickened, dark skin that most commonly occurs in the axilla. It is associated with disorders such as obesity and insulin resistance. It may also be associated with hypothyroidism and other endocrinological processes. Lastly, I do have to mention that it may also be the external manifestation of an underlying tumor.

I would suggest that you have your primary care physician evaluate you and decide on referral to a dermatologist, if needed.

Thank you for this opportunity to answer your questions, I hope you find the information I have provided useful, good luck.