I’ve been reflecting on the various triggers to my eczema during this never-ending but constantly changing topical steroid withdrawal and at 2am this morning I came to a realization. My skin tends to itch like crazy when I’m exposed to something wet in short bursts. This includes actions like washing my hands, dipping my feet in a tub to test the temperature, applying lotions to dry skin, etc.
This realization made me backtrack and first want to know what is the stimuli the body responds to when it’s wetted. We have receptors for temperature (thermoreceptors) and chemicals (chemoreceptors), and even some for painful exposure broadly (nociceptors). We also have cutaneous receptors that can detect pressure, touch, stretch, and vibrations, but still none of those seemed intuitive for how wetness would be recognized. Obviously it’s got a temperature component but that wouldn’t work alone. I did a quick google search and came across this article, which explained that wetness is registered a mix of cold temperature, pressure, and texture reception in tandem with learned experiences to create what was called “perceptual illusion”. Note, I have cited a secondary source above, not the primary study. The study itself I couldn’t access fully, but it is here.
I thought about the information I read and concluded that it didn’t help to explain why my eczema-afflicted skin reacts so aggressively to short duration bursts of wetness. Perhaps it has something to do with the over-sensitization nature of eczema. Maybe if the A-nerve afferents are just more reactive in general, inconsistent exposure (like multiple drops of water hitting my skin) would cause the A-nerve afferents to send tactile/temperature information repeatedly. Then as the over-sensitization makes me register many sensations as an itch, it would just create more itching. Maybe?
Hey, if what you read seemed dated or familiar, I’ve been combining all my other blogs’ content to this site. Please bear with me as I post older content. 🙂