Beta-Alanine and Aquagenic Pruritus: Proposed Neuroimmune Mechanism

TL;DR

This paper suggests that beta-alanine may help relieve aquagenic pruritus by modulating a neuroimmune pathway involving mast cells and sensory neurons.

Contribution

The paper proposes a novel neuroimmune mechanism for beta-alanine's antipruritic effects in aquagenic pruritus.

Findings

Clinical reports show symptom improvement in AP patients using beta-alanine.

MrgprD-expressing neurons may suppress mast cell activity through glutamate release.

Beta-alanine's conversion to carnosine may stabilize mast cells and reduce itching.

Abstract

Aquagenic pruritus (AP) is a rare itch disorder with limited effective treatments, and emerging clinical observations suggest that oral β-alanine may reduce symptoms. The purpose of this viewpoint is to propose a biologically plausible mechanism through which β-alanine may alleviate primary AP. We reviewed published case reports and patient-reported survey data describing β-alanine use in AP and integrated these clinical observations with experimental data on MAS-related G protein–coupled receptor D (MrgprD)–expressing sensory neurons and their role in mast-cell regulation. Published case reports describe marked improvement in water-induced pruritus following prophylactic oral β-alanine administration, and a recent survey of patients with idiopathic AP reported substantial symptom relief among β-alanine users. Preclinical data indicate that MrgprD-neuronal glutamate release suppresses mast cell hyperresponsiveness, suggesting a potential pathway for the observed antipruritic effect. Additional mechanisms, including β-alanine metabolism to carnosine and its potential mast cell–stabilizing effects, may also contribute. β-alanine may act through modulation of a nonhistaminergic neuroimmune circuit and represents a promising therapeutic candidate for further investigation in AP.