A combination of low-dose systemic etretinate and topical calcipotriol/betamethasone dipropionate treatment for hyperkeratosis and itching in Olmsted syndrome associated with a TRPV3 mutation

<p>Feasibility Study for the Long-Term Management of Refractory Hyperkeratotic Eczema with Calcipotriol and Betamethasone Dipropionate (Daivobet^®), Viaminate and Concomitant Conventional Therapies: A Retrospective Study</p>

Background

The available treatments for refractory hyperkeratotic eczema are inadequate with frustrating results. We, therefore, incorporated Calcipotriol and Betamethasone Dipropionate (Daivobet^®), and Viaminate into the mainstay treatment to improve the clinical symptoms. The study aimed to evaluate the efficacy of Daivobet^® and Viaminate as a potential treatment alternative for refractory hyperkeratotic eczema.

Patients and Methods

Between 2013 and 2015, 61 patients diagnosed with refractory hyperkeratotic eczema (RHE) who had shown inadequate response to conventional therapies were pooled from a single center. Besides, they were all treated with Daivobet^®, Viaminate, and an occlusive dressing mixture containing 5% salicylic acid ointment and 25% zinc oxide paste following inadequate response to conventional therapies (corticosteroids plus 25% zinc oxide paste and 5% salicylic acid ointment). Investigators Global Assessment (IGA) and Patient-Oriented Eczema Measure (POEM) assessed baseline and outcome measures for the degree of hyperkeratinization (0-clear; 3-moderate; 4-severe).

Results

Of the 61 patients, 49 (80.3%) patients presented with moderate RHE and 12 (19.7%) with severe RHE. After 24 weeks of treatment, the period for loss of keratinization was significantly lower in patients with moderate RHE (3.9±1.9 weeks) than those with severe RHE (10.8±1.0 weeks) with a P-value <0.01. Furthermore, they required a significantly shorter total treatment duration (10.6 ± 4.3 weeks) than those with severe RHE (20.3±3.6 weeks) with a P-value of <0.01. However, there were no significant differences in post hoc analysis at week 36 with P-values of 0.46 and 1.00 for IGA and POEM, respectively.

Conclusion

Our results showed that the incorporation of Viaminate and Daivobet^® into mainstay treatment was effective and safe for the long-term management of RHE.

Genotype‒Phenotype Correlation of TRPV3-Related Olmsted Syndrome

We have previously shown that gain-of-function variations in transient receptor potential vanilloid-3 (TRPV3) underlay Olmsted syndrome, a rare hyperkeratotic skin channelopathy. In this study, we attempt to establish a genotype‒phenotype correlation in Olmsted syndrome, which has been unclear owing to the rarity and heterogeneity of the condition. We identified five previously unreported TRPV3 variations (R416Q, R416W, L655P, W692S, and L694P) and three recurrent variations (G568D, G568V, and L673F) in nine unrelated patients. Seven variants were expressed in human embryonic kidney 293 cells, and channel behavior was characterized electrophysiologically, with results compared with the clinical severity. These variant TRPV3 channels, in either homomeric or heteromeric form, exhibited differentially elevated basal open probability, increased voltage sensitivity, and cytotoxicity. Functional changes were particularly pronounced in variants corresponding to severer Olmsted syndrome (e.g., L673F and W692S) but not in mild Olmsted syndrome variants (e.g., R416Q). Interestingly, the extent of functional rescue by wild-type TRPV3 in vitro was also consistent with the clinical severity of the variants. These findings, in combination with all reported cases, indicate a preliminary genotype‒phenotype correlation, that is, variations in the S4‒S5 linker and transient receptor potential domain of TRPV3 significantly enhance channel function, causing severe phenotype, whereas other variations appear to exert milder effects on channel function and disease phenotype.

Treatment of hereditary palmoplantar keratoderma: a review by analysis of the literature

BACKGROUND

No specific or curative therapy exists for hereditary palmoplantar keratoderma (hPPK), which can profoundly alter patient quality of life, leading sometimes to severe functional impairment and pain. The rarity and the aetiological diversity of this group of disorders can explain the difficulty in comparing the efficacy of available treatments.

OBJECTIVES

To review the different treatments tried in patients with hPPK since 2008, their efficacy and safety, with an evaluation of the various therapeutic modalities that can be used to treat hPPK.

METHODS

We undertook a comprehensive review of the literature data published since 2008.

RESULTS

Only a few case series and individual case reports were identified. Topical (emollients, keratolytics, retinoids, steroids) and systemic treatments (mostly different retinoids), often combined, are used to relieve symptoms. Oral retinoids appear to be the most efficient treatment, but not in all PPK forms, and with variable tolerance. New targeted treatments, according to the specific mechanisms of hPPK, appear promising for the future.

CONCLUSIONS

More studies using robust methodology and involving larger cohorts of well-characterized patients (phenotype-genotype) are necessary and should be prioritized by structured networks, such as the European Network for Rare Skin Diseases (ERN-Skin), with the aim of better management of patients with rare skin diseases.