What are the key clinical features that differentiate between atopic dermatitis and contact dermatitis in adults?

Differentiating atopic dermatitis from contact dermatitis in adults involves considering their underlying causes, typical presentation, and diagnostic approaches:

• Cause: Atopic dermatitis is a chronic, endogenous condition often associated with a personal or family history of other atopic conditions like asthma or allergic rhinitis ²,³. In contrast, contact dermatitis is caused by an external exposure to a specific irritant or allergen ¹.
• Distribution and Pattern: Atopic dermatitis typically presents with itchy skin and visible dermatitis, often involving the flexural areas (e.g., bends of elbows or behind knees) ³. While contact dermatitis can occur anywhere exposed to the causative agent, hand and facial dermatitis are frequently highlighted as areas where it can be severe, chronic, or recurrent ¹.
• Diagnostic Approach: For atopic dermatitis, diagnosis relies on clinical features, including itchy skin plus a combination of other criteria such as flexural involvement, dry skin, and a history of atopic conditions ³. For contact dermatitis, identifying the causative agent is crucial, and patch testing is often recommended for chronic or persistent cases, particularly hand and facial dermatitis, because clinical features alone may not reliably distinguish it from other forms of dermatitis ¹.
• Course and Management: Atopic dermatitis is characterized by chronic flares, which can usually be controlled with appropriate treatment, including frequent and liberal use of emollients ². Contact dermatitis management primarily focuses on avoidance of the identified stimulus, which is the most important element of treatment and prevention, although it may still persist and require long-term treatment ¹.