The persistence of allergic contact sensitivity: a 10-year follow-up in 100 patients

One hundred patients with 161 positive patch test reactions to a number of common allergic sensitizers were re‐examined after a period of 10 years, using the same patch test technique. Out of 161 positive patch test reactions, ninety‐four (59%) remained positive, forty‐four (27%) had diminished reactivity and twenty‐two (14%) had become negative.