Glucocorticoid treatment increases the risk of opportunistic infection. Infections that can arise during glucocorticoid use, and for which preventative measures can be taken, include reactivation of latent tuberculosis and hepatitis B, pneumococcal and Pneumocystis jiroveci pneumonia, influenza, herpes zoster and Strongyloides stercoralis hyperinfection syndrome. The risk of such infections depends upon the duration of glucocorticoid use and dosage, as well as comorbidity and comedication. It is important to enquire about vaccinations, travel, exposure and previous infections when taking a case history. Possible infectious complications should be considered in patients who are receiving high-dose glucocorticoids treatment amounting to more than 420 mg PED per 4 weeks. Preventative measures are not usually required in patients who receive a short high-dosed treatment (30 mg PED in 7 days) or prednisolone at a dosage of < 15 mg/day.