Doctors Lounge - Dermatology Answers
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Forum Name: Dermatology Topics
Question: dark skin patches
|jacluc - Thu Jun 19, 2008 5:37 am|
My son is 6 years old. He is healthy with the exception of having hypotonia caused by menengitis at 5 weeks old. He has had a rocky start with developmental delays (gross motor, speech, and feeding).
Several years ago he developed a dark patch on his upper left arm. His pediatrician at the time was not concerned. Since then it has spread downward past the elbow. So I would say is covers from just under the shoulder to just past the elbow. In the summer it is very dark but is still obvious throughout the winter months. A few months ago a small patch on the upper right arm began and since the "sun" weather has begun again this year, the patch on the left arm seems to be spreading up over the shoulder onto his back. There are also a couple of small dark spots on his stomach and back (these showed up after sun exposure.) He was seen by an endocrinologist due to unexplained weight gain and night sweats but the doctor did not seem concerned about the patches. His thyroid was checked and his cortisol levels were also checked and were normal. A nutritionist was concerned that they implicated insulin resistance but the endo disagreed. He was seen by a doctor at a childrens hospital for a feeding evaluation and she said it was hyperpigmentation and that I should get another endo opinion because it seems hormonal to her when put together with the weight gain and such. I don't want him to look disfigured by all of these dark patches on his body. Any ideas on what it could be and is there a way to stop it?
|John Kenyon, CNA - Mon Aug 11, 2008 10:11 pm|
While the first disorder that comes to mind would be Addison's disease (cortisol deficiency due to underactivity of the adrenals), there seems to be some disagreement among the health professionals following your son for this problem. There are certain things which might argue for Addison's in his case, such as the developmental delays mentioned, as well as the hypotonia, which, although attributed to meningitis, is also often associated with Addison's disease.
I would concur with the doctor at the children's hospital that the problem sounds endocrinological and an endo consult (second opinion) would definitely be in order. There are just too many suggestive factors here to ignore the possibility.
Good luck to you with this and I hope you'll keep in touch with us here and let us know what you learn.
|Dr. Chan Lowe - Mon Aug 11, 2008 10:21 pm|
Unfortunately, I can't really give you a definite diagnosis as to what this is but I can give you a few thoughts that might help.
First, I agree with the endocrinologist that this does not sound like insulin resistance. Insulin resistance gives a classic hyperpigmentation rash called acanthosis nigricans. It classically is located on the back of the neck, and the finger joints. It would be very unusual for this to present as you have described.
John has suggested Addison's disease, which definitely can cause hyperpigmentation and can show up at this age. It may be worth checking a cortisol level, although I would expect that the hyperpigmentation of Addisons should be more diffuse and symmetrical. This is because in Addison's disease, the brain is making extra ACTH to try to stimulate the adrenal glands, as a byproduct, the melanin glands are also stimulated to produce more pigment. This effect is global so the pigmentation changes should also be throughout the body.
One possibility is a cafe au lait spot, although it really doesn't sound like this to me. A congenital nevus can look this way but I'm less familiar with these showing up so late.
I would recommend your son see a dermatologist. If one is not available, a skin punch biopsy of the area may provide some answers as well. Again, I think going down the endocrinology path is unlikely to be of help. However, if this is continuing to be a question, doing a fasting insulin level or c-peptide level will answer this for you. If it is normal, this is not related to insulin resistance.
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