Acral peeling in Nagashima type palmo-plantar keratosis patients reveals the role of serine protease inhibitor B 7 in keratinocyte adhesion.

Acral peeling skin syndrome (APSS) is a heterogenous group of genodermatoses, manifested by peeling of palmo-plantar skin and occasionally associated with erythema and epidermal thickening. A subset of APSS is caused by mutations in protease inhibitor encoding genes, resulting in unopposed protease activity and desmosomal degradation and/or mis-localization, leading to enhanced epidermal desquamation. We investigated two Arab-Muslim siblings with mild keratoderma and prominent APSS since infancy. Genetic analysis disclosed a homozygous mutation in SERPINB7, c.796C > T, which is the founder mutation in Nagashima type palmo-plantar keratosis (NPPK). Although not previously formally reported, APSS was found in other patients with NPPK. We hypothesized that loss of SERPINB7 function might contribute to the peeling phenotype through impairment of keratinocyte adhesion, similar to other protease inhibitor mutations that cause APSS. Mis-localization of desmosomal components was observed in a patient plantar biopsy compared with a biopsy from an age- and gender-matched healthy control. Silencing of SERPINB7 in normal human epidermal keratinocytes led to increased cell sheet fragmentation upon mechanical stress. Immunostaining showed reduced expression of desmoglein 1 and desmocollin 1. This study shows that in addition to stratum corneum perturbation, loss of SERPINB7 disrupts desmosomal components, which could lead to desquamation, manifested by skin peeling.

Scarring Alopecia in Tumor Necrosis Factor-α Antagonists-Induced Scalp Psoriasis.

Background: A broad spectrum of adverse reactions associated with the use of tumor necrosis factor alpha (TNFα) antagonists has been recognized over the past years. Induction of scalp psoriasis is a less known undesirable consequence of the use of these drugs and is not well characterized. Objective: To characterize TNFα inhibitors-induced psoriatic alopecia. Methods: We studied 6 patients with TNF-inhibitor induced psoriatic alopecia and reviewed 28 patients with this condition reported in the literature to date. Results: In addition to severe scalp psoriasis, we report hair follicle pathologies ranging from alopecia areata to scarring alopecia. Prognosis was good, but discontinuation of TNFα inhibitors was required in more than half of the cases in order to achieve a favourable outcome. Conclusion: TNFα inhibitors-associated psoriatic alopecia is rarely reported but requires a high index of suspicion and prompt diagnosis, as timely intervention may prevent irreversible damage.