Psoriasis — NZ Condition Guide | KiwiMeds

What is Psoriasis?

Psoriasis is a chronic autoimmune skin condition that causes skin cells to multiply too rapidly, building up into thick, scaly patches on the skin surface. It affects around 2–3% of New Zealanders. Psoriasis is not contagious. It often has a significant impact on quality of life — not only physically but also psychologically, as visible plaques can cause embarrassment and social withdrawal.

Overview

The most common type is plaque psoriasis — raised, red patches covered with silvery-white scales, most commonly on the elbows, knees, scalp, and lower back. Other types include guttate (small teardrop-shaped spots, often triggered by streptococcal throat infection), inverse (in skin folds), pustular, and erythrodermic. Psoriatic arthritis — joint inflammation — affects around 30% of people with psoriasis. Psoriasis is associated with cardiovascular disease, metabolic syndrome, and depression.

Treatment in New Zealand

Treatment depends on severity. Topical therapies (corticosteroid creams, vitamin D analogues such as calcipotriol, coal tar, dithranol) are first-line for mild-moderate psoriasis and are Pharmac-funded. Phototherapy (UV light treatment) is effective for moderate-severe psoriasis. Systemic treatments for severe psoriasis include methotrexate, acitretin, and cyclosporine. Biologic medicines (adalimumab, secukinumab, ustekinumab, ixekizumab) are now funded by Pharmac for severe psoriasis meeting criteria — they have transformed outcomes for severe disease.

NZ-Specific Information

The Psoriasis Association of NZ provides support and information. Pharmac funds biologic medicines for severe psoriasis — specialist dermatologist referral is required to access these. Skin cancer risk from UV exposure means phototherapy is carefully monitored.

Frequently Asked Questions

Can psoriasis be cured? Not cured, but it can be very well controlled with the right treatment. Many people achieve clear or near-clear skin with biologics. Can stress trigger psoriasis? Yes — stress is a well-recognised psoriasis trigger. Is psoriasis hereditary? Yes — genetics play a significant role. If both parents have psoriasis, the risk for children is around 50%.

Supplements That May Support Management

⚠️ Important: The supplements listed below have varying levels of clinical evidence. They are not a substitute for prescribed medications and should only be considered as adjunctive support under the guidance of a qualified healthcare professional. Always inform your GP or pharmacist before commencing any supplement, as interactions with prescribed medicines are possible.

• Vitamin D (oral and topical) — Vitamin D has both immunomodulatory effects and direct anti-proliferative activity on keratinocytes. Oral supplementation is appropriate where systemic deficiency is confirmed. Topical vitamin D analogues (calcipotriol) are a standard first-line treatment for plaque psoriasis.
• Omega-3 Fatty Acids — High-dose fish oil supplementation (≥3 g/day EPA+DHA) has demonstrated reductions in psoriasis severity scores in several trials, reducing keratinocyte proliferation and inflammatory cytokine production relevant to psoriatic plaques.
• Vitamin B12 (topical emulsions) — Topical vitamin B12 formulations have been used in psoriasis management in Europe, with some trial evidence supporting reductions in plaque severity, potentially via antioxidant mechanisms.
• Turmeric/Curcumin — Curcumin inhibits NF-κB and TNF-α pathways central to psoriatic inflammation. At doses of 1.5–4.5 g/day with enhanced bioavailability, small trials have demonstrated improvements in psoriasis area severity scores.
• Zinc — Zinc has anti-inflammatory properties and plays a role in skin cell turnover regulation. Supplementation may be beneficial in those with documented deficiency, which is more common in psoriasis.

Relevant Vaccinations

Individuals living with psoriasis may benefit from the following vaccinations. Please discuss your vaccination status with your GP or practice nurse, as eligibility and funding through the New Zealand National Immunisation Schedule may apply.

• Influenza (annual) — Viral infections are known psoriasis triggers. Annual influenza vaccination reduces trigger exposure.
• COVID-19 — People on biologic therapies for psoriasis (TNF inhibitors, IL-17/23 inhibitors) should maintain up-to-date COVID-19 vaccination. Discuss timing of vaccination relative to biologic dosing with your dermatologist or rheumatologist.
• Pneumococcal — Recommended for people on biologic immunosuppressive therapies for psoriasis.
• Shingles (Shingrix) — Recommended for adults on biologic therapies who are ≥50 years, as immunosuppression increases herpes zoster risk.

Dietary Guidance

Evidence-based dietary modifications play a meaningful role in the management of psoriasis. The following foods are generally recommended as part of a balanced, condition-appropriate diet. A referral to a registered dietitian may be beneficial for personalised nutritional planning.

• Anti-inflammatory Mediterranean dietary pattern — The Mediterranean diet is associated with reduced psoriasis severity in observational studies. Its anti-inflammatory composition targets the TNF-α and IL-17 pathways central to psoriatic inflammation.
• Oily fish (omega-3 source) — Regular dietary omega-3 from fish reduces inflammatory eicosanoid production relevant to keratinocyte proliferation and plaque formation.
• Colourful fruits and vegetables — Rich in antioxidants and polyphenols that reduce oxidative stress elevated in psoriatic skin.
• Limit: alcohol — Alcohol is one of the strongest dietary psoriasis triggers, associated with increased disease severity and reduced treatment response. Reduction or abstinence significantly improves psoriasis control.
• Limit: processed foods, refined sugars — High-glycaemic and ultra-processed diets promote systemic inflammation and are associated with worse psoriasis outcomes. Weight management is also important as obesity worsens psoriasis and reduces biologic efficacy.

Related Conditions & Medications

Related conditions: Rheumatoid Arthritis, Eczema.