Allergic Contact Dermatitis by Anatomical Regions: Diagnostic Clues.

Allergic contact dermatitis (ACD) is a common disease in daily clinical practice, and its prevalence has increased in recent years. It is characterized clinically by varying degrees of erythema, vesiculation, flaking, and lichenification, though these signs can also be present in other eczematous diseases. Patch testing is the main diagnostic tool to confirm ACD, but its accurate interpretation requires correct correlation with the medical history (details of exposure) and physical examination. We provide a practical and instructive description of the most common clinical patters of ACD depending on the area affected. Knowledge of these patterns will not only help the clinician reach the diagnosis but will suggest possible allergens and forms of contact.