BH05 Eighteen years’ experience of grenz ray therapy for the treatment of nail disorders: a single-centre retrospective study

Abstract

Nail disorders present significant therapeutic challenges with limited treatment options. Grenz ray therapy utilizes soft X-rays that penetrate superficial tissues while sparing deeper structures, offering a noninvasive treatment modality. Despite historical use, contemporary effectiveness data remain limited. We aimed to evaluate the effectiveness of grenz ray therapy for various nail disorders through retrospective analysis of 18 years’ experience at a UK tertiary dermatology centre. This was a retrospective cohort study of 79 treatment courses in 51 patients treated with grenz rays at a UK tertiary dermatology centre (2000 to early 2018). Diagnoses include nail psoriasis, idiopathic onycholysis, acropustulosis of Hallopeau, nail lichen planus, chronic paronychia, yellow nail syndrome, cutaneous T-cell lymphoma and nail dystrophy in Raynaud phenomenon. Patients received weekly or biweekly sessions. Cumulative doses per course ranged from 16 to 65 Gy. Treatment outcomes were categorized as no change, slight improvement (< 50%), good improvement 50–75%), marked improvement (> 75%) or clearance. Outcomes were grouped into two main categories: ‘any response’ (slight improvement or better) and ‘significant response’ (good improvement or better). The mean patient age was 52.1 years (range 20–84), with 65% female. Overall, 72% achieved any response, while 33% achieved significant response. Nail psoriasis, the most common indication (67% of treatment courses), demonstrated 77% any response and 36% significant response. Acropustulosis of Hallopeau showed the highest response rates (80% any response, 40% significant response), while yellow nail syndrome showed no response. The optimal cumulative dose was 26–30 Gy, achieving 87% response rate. Treatment response showed a complex age-related pattern: older patients were more likely to achieve any response, while patients in the middle age bands demonstrated the highest rates of significant response. Grenz ray therapy demonstrates moderate effectiveness for inflammatory nail disorders, particularly nail psoriasis and acropustulosis of Hallopeau, with optimal dosing at 26–30 Gy. However, it is ineffective for structural disorders like yellow nail syndrome. This supports its role as a targeted option for patients unsuitable for systemic therapy.