Case Of Profuse Local Sweating In A Healthy Neonate

A 2 week old healthy and thriving boy with profuse sweating on his lower back. No syndromic facial features. FBE, TFT, Electrolytes, LFT - NAD.

Spinal and renal ultrasound - NAD. Mother has Hashimoto thyroiditis and not on medications, last TFT done during pregnancy. What are the differentials to considered?