comparison of irritant and allergic dermatitis

Last reviewed 09/2019

  primary irritant allergic contact
Prior exposure none required sensitisation needed to substance
Spread little extension from contact site may spread to sites not in direct contact
Association atopy predisposes prolonged use of topical medicaments may predispose
Susceptibility everyone only certain people
Course Rapid onset within 4-12 hours. Lesions develop on first exposure Onset usually after 24 hours. No lesions on first exposure.