There are 12 questions in this quiz, which will test your skills at identifying the cause of an irritant contact dermatitis.
Contact irritant dermatitis is due to direct cellular injury following a single or repeated application of a chemical substance or friction to the skin. The responsible agents are often multiple, and may include acids, alkalis and oxidants (chemical burns) or low-grade irritants such as soaps, detergents and solvents. The degree of cutaneous injury will depend on chemical concentration, pH, environmental temperature, occlusion and duration of contact. The skin barrier is disrupted and there is an inflammatory response, but it is not due to allergy to responsible agents so patch tests are negative.
Irritant dermatitis is more common than allergic contact dermatitis and is the usual reason for occupational dermatitis. It arises at lower threshold in atopics or in those with pre-existing dermatitis of any type.
Acute contact irritant dermatitis presents with erythema, scaling, oedema, vesiculation and erosions. Chronic irritant dermatitis presents with erythema, lichenification, hyperkeratosis and fissuring. This may be very similar or indistinguishable from allergic contact dermatitis. However, irritant dermatitis tends to be confined to the site of injury, whereas an allergic reaction tends to spread.
It is important to remove and/or protect affected skin from contact with the source of irritation, using barrier creams and gloves where appropriate. Topical steroids are prescribed for up to several weeks as anti-inflammatory agents, and bland emollients should be applied frequently to soothe and relieve dryness.
For each of the twelve cases, study the image(s) and then answer the questions. You can click on the image to view a larger version if required.
Each case should take approximately 2 minutes to complete. There is a list of suggested further reading material at the end of the quiz.
When you finish the quiz, you can download a certificate.
What is the patient reacting to?
Describe the clinical features.
