Does nail biting cause serious problems? What are they?

Yes, nail biting can cause potential health issues. In the short term, biting your nails can break or damage the skin around the nails, causing pain and potentially introducing bacteria that can lead to infections.  Long-term effects of nail biting include:

Damage to dental enamel - Nail biting may also wear away at your teeth’s protective coating leading to enamel erosion and an increased risk of cavities over time.
Infections – The skin around your nails is incredibly delicate, making it susceptible to bacterial infection if it is damaged by nail-biting or other habits such as picking at hangnails. This can be especially dangerous for those with reduced immunity due to chronic illnesses like HIV/AIDS or cancer treatment medications.
An increase in allergic reactions – Biting and picking at your nails may make you more sensitive when it comes to allergens such as pollen or pet dander which could result in higher levels of allergies and asthma symptoms over time due recent studies done on this subject .
Unsightly hands – Constant nail-biting makes fingers look worn down and jagged which causes them not only be unappealing but will also make people think twice before shaking your hand! Furthermore, if left unchecked this habit could lead up permanent damage like ridges on finger tips too!