Erythromycin can be applied to itchy inner thighs, but this medication may not be suitable for all patients. Erythromycin is an antibiotic that has a therapeutic effect on itchy inner thighs caused by bacterial infections. Some patients with other skin conditions have used this medication and instead of having the appropriate therapeutic effect, the condition has worsened. Therefore, it is not recommended that patients intervene with medication on their own before a diagnosis is made.