When topical creams are no longer effective for severe eczema or psoriasis, doctors may prescribe systemic immunosuppressants. These medications, such as methotrexate, ciclosporin, and azathioprine, work by dampening the overactive immune response that causes skin inflammation. While they are highly effective, they are not as targeted as newer biological therapies and can affect the entire body. In the UK, these treatments are managed under strict safety protocols to monitor for potential side effects. Understanding these risks is a vital part of the shared decision-making process between a patient and their dermatologist.
What We’ll Discuss in This Article
- The increased risk of bacterial, viral, and fungal infections.
- Potential toxicity to major organs like the liver and kidneys.
- Suppression of the bone marrow and its effect on blood counts.
- The importance of regular blood test monitoring in the UK.
- Specific drug-related side effects such as nausea or gum overgrowth.
- Risks related to pregnancy and long-term health.
1. Increased vulnerability to infections
The primary role of an immunosuppressant is to turn down the volume of the immune system. While this reduces skin inflammation, it also means the body is less able to defend itself against common pathogens.
- Common Infections: Patients may experience more frequent or severe colds, sore throats, or urinary tract infections.
- Opportunistic Infections: There is a slightly higher risk of unusual infections that a healthy immune system would typically handle, such as shingles (the reactivation of the chickenpox virus).
- Latent Infections: Before starting treatment, the NHS requires screening for dormant infections like tuberculosis (TB) or hepatitis, as these can reactivate when the immune system is suppressed.
2. Organ toxicity and monitoring
Some systemic medications can place a strain on specific organs as they are processed by the body.
- Liver Function: Methotrexate is known to potentially affect the liver over a long period. Regular blood tests check for elevated liver enzymes, which indicate the organ is under stress.
- Kidney Function: Ciclosporin can impact the kidneys and may also lead to an increase in blood pressure. Because of this, patients on ciclosporin require regular blood pressure checks alongside their blood tests.
- Monitoring: In the UK, these tests typically occur every 2 to 4 weeks during the start of treatment, eventually moving to every 3 months once the patient is stable.
3. Impact on blood cells (Bone Marrow Suppression)
The bone marrow is responsible for producing red blood cells, white blood cells, and platelets. Some immunosuppressants can slow this production down.
- Anaemia: A drop in red blood cells can lead to persistent tiredness and shortness of breath.
- Leukopenia: A drop in white blood cells significantly increases the risk of serious infection.
- Thrombocytopenia: A drop in platelets can lead to easy bruising or unexplained bleeding, such as frequent nosebleeds.
4. Specific drug-related side effects
Each immunosuppressant has a unique profile of potential “nuisance” side effects that, while not always dangerous, can affect quality of life:
- Methotrexate: Often causes nausea, fatigue, or mouth ulcers, particularly in the 24 to 48 hours after the weekly dose. Taking a folic acid supplement is standard practice in the UK to help reduce these effects.
- Ciclosporin: May cause a tingling sensation in the hands and feet, increased hair growth (hypertrichosis), or swollen gums (gingival hyperplasia).
- Azathioprine: Can cause significant stomach upset or a specific type of sensitivity to sunlight.
5. Risks during pregnancy and conception
Many systemic immunosuppressants have significant risks if taken during pregnancy.
- Methotrexate: This medication is teratogenic, meaning it can cause serious birth defects or miscarriage. Both men and women must use effective contraception while taking it and for at least six months after stopping.
- Acitretin: For women, this medication must be avoided if pregnancy is planned within the next three years, as it stays in the body for a very long time.
- Specialist Advice: If you are planning a family, your dermatologist will help you transition to safer alternatives, such as certain biological therapies or ultraviolet light treatment.
6. Long-term health considerations
There is a very small but statistically significant increase in the risk of certain cancers, particularly non-melanoma skin cancers, with the long-term use of some immunosuppressants. For this reason, patients are advised to practice strict sun safety and to report any new or changing moles or skin lesions to their doctor immediately.
Conclusion
Immunosuppressive treatments are powerful tools that can bring life-changing relief to those with severe eczema or psoriasis. However, they require a commitment to regular medical supervision and lifestyle adjustments. By adhering to the UK monitoring protocols and being aware of the signs of infection or organ stress, most patients can use these medications safely for many years. Always discuss the balance of risk and benefit with your specialist to ensure the chosen treatment aligns with your overall health goals.
What should I do if I feel unwell while on an immunosuppressant?
If you develop a high fever, a severe sore throat, or a persistent cough, you should contact your GP or dermatology team immediately. Do not wait for your next scheduled blood test.
Can I still have vaccinations?
You should avoid “live” vaccines (such as the yellow fever or shingles vaccines) while on immunosuppressants. Most “inactivated” vaccines, like the annual flu jab or COVID-19 vaccines, are safe and recommended.
Why do I need to take folic acid with methotrexate?
Methotrexate interferes with how the body uses folate. Taking a prescribed folic acid supplement helps protect your healthy cells and reduces side effects like mouth ulcers and nausea.
Does alcohol affect these medications?
Alcohol can increase the risk of liver damage when taking methotrexate. Most UK clinicians advise keeping alcohol intake well within the recommended 14 units per week, or avoiding it entirely.
Will I be on these medications forever?
Not necessarily. Many people use them to get their condition under control and may eventually trial a lower dose or a “drug holiday” under the guidance of their dermatologist.
Can these medications affect my mood?
While not a common side effect of the drugs themselves, the stress of managing a severe condition and a complex medication regime can impact mental health. Always share your emotional well-being with your doctor.
Is it safe to go on holiday while taking these?
Yes, but you must ensure you have enough medication and your blood tests are up to date. You should also be extra vigilant with sun protection as many of these drugs increase sun sensitivity.
Authority Snapshot (E-E-A-T Block)
This article examines the clinical risks and monitoring requirements associated with systemic immunosuppressants for skin conditions. It is written by the MyPatientAdvice Medical Writing/Research Team and reviewed by Dr. Rebecca Fernandez, a UK-trained physician with experience in chronic disease management and internal medicine. All guidance is strictly aligned with the safety standards provided by the NHS and NICE for 2026.
