The most consistent and distinctive clinical feature of an HSAN is loss of pain and temperature perception. However the degree of loss will vary among the different HSAN with FD or HSAN type 3 having relatively less severe problems and CIPA (HSAN type IV) and HSAN type II having profound sensory loss and being at greater risk for self-injury. Because of the decreased pain perception some of the following symptoms may be noted:

• painless fractures and other orthopedic problems involving joints
  
  
• tongue or lip biting
  
  
• dental problems (early loss of teeth)
  
  
• skin sores
  
  
• corneal ulcerations

Only CIPA or HSAN type IV has decreased sweating which puts the patient results in dry skin and risk of high fevers since sweating helps cool the body.

Hyperactivity or learning problems have been noted with some of the HSAN.