Contraindication of local anaesthesia is

(Clotting disorders): Ref: 50. LB (199-B &L 25th)* Contraindication of LA are local infection and clotting disorders, Not only does local infiltration spread the infection, but local anaesthetic drugs are ineffective in condition of acidity as produced by infection. Local infiltration in the presence of a clotting disorder may result in haemorrhage or may produce haematoma, which is potentially fatal in the airway, as may occure in dental surgery.