Which single clinical feature best separates chronic irritant contact dermatitis from allergic contact dermatitis?
- A Irritant dermatitis is sharply demarcated exactly to the area of exposure, while allergic dermatitis may spread beyond the contact site ✓
- B Irritant dermatitis always spares the hands
- C Allergic dermatitis never vesiculates
- D Irritant dermatitis requires prior sensitisation and appears after a latency period of days
Correct answer: A. Irritant dermatitis is sharply demarcated exactly to the area of exposure, while allergic dermatitis may spread beyond the contact site
Explanation
Irritant contact dermatitis is non-immunologic and its borders correspond closely to the exposed area, whereas allergic contact dermatitis is delayed-type hypersensitivity and can extend beyond the contact zone. Option D describes allergy, not irritation, so it kills itself as a distractor. Both types occur on hands and both can vesiculate in acute phases.
Reference: Habif Clinical Dermatology, 6th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.