Can prednisone (corticosteroid) lower immunity, especially in patients with underlying medical conditions such as diabetes, hypertension, or a history of infections?

Can Prednisone Lower Your Immunity?

Yes, prednisone significantly suppresses the immune system in a dose-dependent and duration-dependent manner, increasing susceptibility to infections including bacterial, viral, fungal, and opportunistic pathogens. 1

Mechanism and Extent of Immunosuppression

Prednisone suppresses both cellular and humoral immunity, though effects vary by dose and duration:

• Cell-mediated immunity is predominantly affected, with profound but transient lymphocytopenia occurring 4 hours after each dose, particularly depleting T-cells from circulation 2
• Humoral immunity (antibody production) is also impaired, especially with prolonged use at doses >12.5 mg/day for at least 1 year, which can cause hypogammaglobulinemia 3
• The FDA label explicitly warns that prednisone "suppresses the immune system and increases the risk of infection with any pathogen, including viral, bacterial, fungal, protozoan, or helminthic pathogens" 1

Dose-Dependent Effects on Immunity

The degree of immunosuppression correlates directly with prednisone dosage:

• Low-dose (<10 mg/day): Minimal impact on vaccine responses and immune function; concomitant low-dose corticosteroids (mean 6.2 mg/day) did not adversely affect pneumococcal vaccine responses 4
• Moderate-dose (10-20 mg/day): Some suppression of humoral immunity begins; doses >12.5 mg/day for ≥1 year can cause low serum IgG levels 3
• High-dose (>20 mg/day): Significant immunosuppression occurs; among patients with inflammatory diseases, 57% of pneumococcal vaccine non-responders were taking prednisone >20 mg/day compared with 22% of responders 4
• Very high-dose (>60 mg/day): Severe immunosuppression with markedly increased infection risk 1

Specific Infection Risks

Prednisone increases susceptibility to multiple types of infections:

Opportunistic Infections

• Pneumocystis jirovecii pneumonia (PCP): Consider prophylaxis for patients taking ≥20 mg prednisone for ≥4 weeks 5
• Tuberculosis reactivation: Can occur in patients with latent TB or tuberculin reactivity; close monitoring and chemoprophylaxis recommended during prolonged therapy 1
• Hepatitis B reactivation: Screen patients before initiating immunosuppressive treatment; reactivation can occur even in those with apparently resolved infection 1

Viral Infections

• Varicella and measles: Can have serious or fatal courses in non-immune patients; prophylaxis with immune globulin indicated if exposed 1
• Herpes simplex: Reactivation can occur even with short-term use 6

Fungal and Parasitic Infections

• Systemic fungal infections: Prednisone may exacerbate these; avoid use unless needed to control drug reactions 1
• Strongyloides (threadworm): Use with great care in patients with known or suspected infestation 1
• Amebiasis: May activate latent disease; rule out before initiating therapy in at-risk patients 1

Special Considerations for High-Risk Populations

Patients with Diabetes

• Prednisone commonly causes hyperglycemia and can worsen diabetes control, requiring blood glucose monitoring 5
• Two patients in one study developed hyperglycemia and one diabetic required increased insulin 6
• The combination of immunosuppression and hyperglycemia further increases infection risk 5

Patients with Hypertension

• Prednisone elevates blood pressure through mineralocorticoid-like effects and increased potassium excretion 1
• Regular blood pressure monitoring recommended even during short courses 7

Patients with History of Infections

• The rate of infectious complications increases with increasing corticosteroid dosages 1
• Previous infections may reactivate, particularly TB, hepatitis B, herpes viruses, and parasitic infections 1
• Screen for latent infections before starting therapy when possible 1

Duration-Dependent Effects

The duration of prednisone therapy significantly impacts immune suppression:

• Short courses (≤3 weeks): Minimal lasting immunosuppression; HPA axis suppression typically does not occur 8
• Intermediate courses (3-10 weeks): Some immune effects but generally reversible; tapering may be needed for courses >3-4 weeks at doses ≥20 mg/day 8
• Long-term use (>18 months at >10 mg/day): Significant and potentially prolonged immunosuppression; one case report showed reversible B-cell deficiency resembling common variable immunodeficiency after 36 years of low-dose therapy 9

Vaccine Response Impairment

Prednisone impairs vaccine immunogenicity in a dose-dependent manner:

• High-dose glucocorticoids (>20 mg/day) adversely impact pneumococcal vaccine responses 4
• Low-dose glucocorticoids (<10 mg/day) taken concomitantly with other therapy have not been found to impact pneumococcal vaccine responses 4
• Update all vaccines before starting immunosuppressive therapy when possible 5
• Avoid live vaccines in patients already taking immunosuppressants 5

Critical Clinical Pitfalls to Avoid

• Underestimating infection risk: The FDA warns that corticosteroid-associated infections "can be mild but can be severe and at times fatal" 1
• Missing latent infections: Always screen for TB, hepatitis B, and consider strongyloides in at-risk patients before starting therapy 1
• Ignoring prophylaxis: Failure to provide PCP prophylaxis for patients on ≥20 mg prednisone for ≥4 weeks 5
• Inadequate patient education: Patients must be educated about signs of infection and when to seek immediate medical attention 5
• Masking infection signs: Prednisone can mask typical signs of infection, making diagnosis more difficult 1

Monitoring Recommendations

For patients on prednisone, especially those with underlying conditions:

• Monitor for development of infection and consider dose reduction or withdrawal as needed 1
• Regular blood glucose monitoring, particularly in diabetics or those at risk 5
• Blood pressure monitoring, even during short courses 7
• Screen for latent infections before initiating therapy 1
• Educate patients about infection signs and ensure prompt medical evaluation for fever, new respiratory symptoms, or other concerning findings 5