Skin nerve fibres and their contacts with mast cells in patients with palmoplantar pustulosis

Patients with palmoplantar pustulosis (PPP) frequently report that stress w orsens their condition, A study was therefore made of the distribution and number of nerve fibres positive for protein gene product (PSP) 9.5 (a gener al nerve marker) and nerve fibres with substance P- and calcitonin gene-rel ated peptide-like immunoreactivity in involved skin from patients with PPP and in skin from healthy controls. The number of mast cells in the papillar y dermis was larger (P = 0.0003) in lesional palmar PPP skin than in contro l skin, and the number of contacts between mast cells and nerve fibres was significantly larger (P = 0.02) in PPP skin than in control skin. Image ana lysis of the nerve fibres around the sweat glands showed that the positivel y stained area as a percentage of the total area of the sweat gland (coil surrounding nerves) was significantly lower in PPP skin (P = 0.0006). Furt hermore, the nerves seemed to be fragmented. Neutrophils within and below t he pustules and in the papillary dermis showed positive substance P stainin g. The increased number of contacts between nerves and mast cells in PPP sk in and the intense substance P-like immunoreactivity of the neutrophils ind icate that neuromediation may influence the inflammation in PPP, whereas th e destruction of the nerve fibres around the sn-eat glands might be a resul t of the inflammation.