Interventions for chronic palmoplantar pustulosis

Background: Palmoplantar pustulosis is a chronic inflammatory disease in which sterile, relapsing pustules appear on the palms and soles, possibly in conjunction with other symptoms. The previous Cochrane Review on this topic was published in 2006, before biological treatments were extensively used.

Objectives: To assess the effects of interventions for chronic palmoplantar pustulosis to induce and maintain complete remission.

Search methods: We searched the following databases up to March 2019: Cochrane Skin Specialised Register, CENTRAL, MEDLINE, Embase, and LILACS. We also searched five trials registers and checked the reference lists of the included studies for further references to relevant randomised controlled trials (RCTs).

Selection criteria: We considered RCTs including people with palmoplantar pustulosis or chronic palmoplantar pustular psoriasis assessing topical therapy, systemic therapy, combinations of topical or systemic therapies, or non-pharmacological therapies compared with placebo, no intervention, or each other.

Data collection and analysis: We used standard methodological procedures expected by Cochrane. Our outcomes included 'Proportion of participants cleared or almost cleared', 'Proportion of participants with adverse effects serious or severe enough to cause withdrawal', 'Proportion of participants with at least 50% improvement in disease severity', and 'Proportion of participants with adverse effects'.

Main results: We included 37 studies (1663 participants; mean age 50 years (range 34 to 63); 24% males). These studies reported condition severity differently. Around half of the included trials stated the setting (hospitals, community clinics, or both). More than half of the studies were at high risk of bias in at least one domain. Our included studies assessed mainly systemic treatments (retinoids, ciclosporin, biologics, etretinate + PUVA (combination of psoralens and long-wave ultraviolet radiation) therapy combined, and antibiotics), but also topical treatments (dermocorticoids, vitamin D) and phototherapy (PUVA, ultraviolet A1 (UVA1)). Other interventions were assessed by single studies. The most common comparator was placebo. All results presented in this abstract were assessed in the short term (mean treatment duration was 11 weeks (range 8 to 24 weeks)) and are based on participants with chronic palmoplantar pustulosis. All outcome time point measurements were taken from baseline and assessed at the end of treatment. Short-term and long-term outcomes were defined as measurement up to 24 weeks after randomisation and between 24 and 104 weeks after randomisation, respectively. One trial (188 participants) assessed the topical vitamin D derivative maxacalcitol versus placebo and found that maxacalcitol may be more effective than placebo in achieving clearance (risk ratio (RR) 7.83, 95% confidence interval (CI) 1.85 to 33.12; low-quality evidence), and the risk of adverse effects (such as mild local irritation, pruritus, and haematological or urinary test abnormalities) is probably similar in both groups (RR 0.87, 95% CI 0.64 to 1.19; moderate-quality evidence). Severity was not reported. Two trials (49 participants) assessed PUVA therapy versus placebo or no treatment, providing very low-quality evidence. Adverse effects were reported with oral PUVA (including nausea, ankle swelling, and non-purulent conjunctivitis) and with local PUVA (including blistering, erythema, and pruritus). With regard to the systemic retinoid alitretinoin, one trial (33 participants; moderate-quality evidence) showed that alitretinoin probably makes little or no difference in reducing severity when compared to placebo (RR 0.69, 95% CI 0.36 to 1.30). A similar number of adverse events were reported in both treatment groups, including headache, cheilitis, nausea, arthralgia, and nasopharyngitis (RR 0.84, 95% CI 0.61 to 1.17). Clearance was not reported. There may be little or no difference between etanercept and placebo in achieving clearance (RR 1.64, 95% CI 0.08 to 34.28; 1 study; 15 participants; low-quality evidence); however, the 95% CI was very wide, showing there may be a difference between groups. Severity was not measured. More patients treated with placebo may achieve reduced severity than those treated with ustekinumab, but the wide 95% CI indicates there might be little or no difference between groups and there might be greater effect with ustekinumab (RR 0.48, 95% CI 0.11 to 2.13; 1 study; 33 participants; low-quality evidence). Clearance was not reported. It is uncertain whether guselkumab increases clearance when compared to placebo (2 studies; 154 participants) because the quality of evidence is very low, but guselkumab probably better reduces disease severity (RR 2.88, 95% CI 1.24 to 6.69; 1 study; 49 participants; moderate-quality evidence). Secukinumab is probably superior to placebo in reducing severity (RR 1.55, 95% CI 1.02 to 2.35; 1 study; 157 participants; moderate-quality evidence), but our clearance outcome was not reported. None of these trials reported on occurrence of adverse effects. Only two of the studies discussed above reported adverse effects serious or severe enough to cause withdrawal. Guselkumab may cause more serious adverse events when compared to placebo, but there is uncertainty due to the very wide 95% CI showing there may be little or no difference and showing more events with placebo (RR 2.88, 95% CI 0.32 to 25.80; 1 study; 49 participants; low-quality evidence). Secukinumab probably causes more serious adverse events than placebo (RR 3.29, 95% CI 1.40 to 7.75; 1 study; 157 participants; moderate-quality evidence).

Authors' conclusions: Evidence is lacking for major chronic palmoplantar pustulosis treatments such as superpotent corticosteroids, phototherapy, acitretin, methotrexate, and ciclosporin. Risk of bias and imprecision limit our confidence. Maxacalcitol may be more effective than placebo in achieving clearance in the short term (low-quality evidence), and the risk of adverse effects is probably similar (moderate-quality evidence). Oral alitretinoin is probably no more effective than placebo in reducing severity, with a similar risk of adverse effects (moderate-quality evidence). Regarding biological treatments, we are uncertain of the effect of etanercept on clearance and the effect of ustekinumab on severity (low-quality evidence). Secukinumab and guselkumab are probably superior to placebo in reducing severity (moderate-quality evidence). Adverse events not requiring withdrawal were not reported for these treatments. Reporting of serious adverse effects was incomplete: compared to placebo, secukinumab probably caused more participant withdrawals (moderate-quality evidence), but we are uncertain of the effect of guselkumab (low-quality evidence). Future trials should assess commonly used treatments using validated severity and quality of life scales.