Mast cells degranulate, producing histamine which attracts eosinophils. The early stage of an allergic reaction is mast cell mediated, but the late stage (including mucus production) is mediated by eosinophils.

Recall : Findings on a sputum examination in asthma Curschmann spirals and Charcot Leyden Crystals

Charcot Leyden crystals: are made up of Eosinophils ( and their main active substance - major basic protein )

Curschmann spirals are just whorled mucus plugs formed by shed bronchial epithelium

Main chemoattractant for eosinophils :is not histamine but IL-5 ( which is produced by mast cells and T helper 2 cells)

i never knew eosinophils play a role in mucus secretion

also wanted to add that during late phase of mast cell degradation they release eosinophil chemotactic factor