Eating metronidazole itchy skin, may be the patient to metronidazole allergy, through oral loratadine can be anti-allergy treatment; but if the use of loratadine after taking, may be the persistence of drug allergy, the drug to take the dose is not enough and other factors caused. 1. Drug allergy: itchy skin after eating metronidazole, consider and drug allergy. If you are allergic to the ingredients inside the metronidazole, it may produce itchy symptoms. In severe cases, it can also cause drug rash, especially severe drug rash, the single use of loratadine treatment effect is not good, it is recommended that the systematic application of glucocorticoids, immunosuppressants and other drugs under the guidance of the doctor. 2. Allergen persistence: If it is clear that the itchy skin is caused by metronidazole allergy, it is recommended to stop taking metronidazole, if the persistent use of metronidazole, even if the application of loratadine anti-allergy treatment, still can not achieve good therapeutic effect, itchy skin can be persistent. 3. Insufficient dose of medication: If the dose of loratadine is too small, it will not be able to achieve the role of the treatment of the disease, and will not be able to achieve the effect of anti-allergy, anti-itch, at this time, there may still be itchy skin symptoms. It is recommended that patients stop taking suspicious drugs, go to the regular hospital dermatology consultation, under the guidance of the doctor in the full amount of treatment or replacement of other drugs, do not self-medication delay the condition, resulting in serious adverse reactions.