Yes, your niece suffers from Addisons disease. It is a life threatening disease, hence waiting for confirmation of the disease is sometimes not advisable. Hypoglycemia, hyperpigmentation and salt craving are hallmarks of the disease. The investigations done so far suggest the diagnosis. The diagnosis can be confirmed by estimation of basal and ACTH stimulated cortisol levels. ACTH intravenous injections are often not easily available in many cities of India, but can be procured from Mumbai or Delhi with some effort. The child will need life long replacement of hydrocortiosone. Since the treatment is a replacement of the hormones that are deficient in the body, it does not produce any long term complicatons unlesss excess doses are given.