The Bumps Are Keratin. The Sponge Is How Arms Collect PIH.

Skin Conditions · Published 2026-09-20 · 10 min read · 2051 words

Lactic acid and urea smooth KP. Hard water and a net sponge undo the lotion. Cream damp skin. Leave the sandpaper.

Key takeaways

• Ten percent lactic or ten to twenty percent urea is the workhorse.
• Hard water and hot Highveld showers tighten the plug.
• The net sponge turns bumps into lasting PIH.
• Body SPF belongs on shoulders once sleeves go short.

Source: KP keratolytic review 2025 / lactic-urea trial literature / Isaacs et al. IJD 2025 photoprotection (https://pmc.ncbi.nlm.nih.gov/articles/PMC12860576/)

Cover image: Unsplash — credit