Contact Dermatitis
Skin inflammation from irritants and allergens — avoidance and management
Contact dermatitis is a type of eczema caused by contact with a particular substance. It causes the skin to become red, itchy, blistered or cracked. Contact dermatitis accounts for up to 70% of occupational skin disease and is a significant cause of work-related ill health in the UK.
What is Contact Dermatitis?
Contact dermatitis is an inflammatory skin reaction triggered by contact with an external substance. Unlike atopic eczema, which is driven by an internal immune predisposition, contact dermatitis has a clear external cause. The condition can affect any part of the body that comes into contact with the trigger substance, but the hands are most commonly affected — particularly in people with occupational exposures. Contact dermatitis can be acute (appearing quickly after a single exposure) or chronic (developing gradually with repeated exposure over weeks or months). It is not contagious.
Irritant vs Allergic
Contact dermatitis has two main types. Irritant contact dermatitis (ICD) is the most common type — it is caused by physical or chemical damage to the skin barrier from substances such as soaps, detergents, cleaning products, solvents, wet work and repeated hand washing. Anyone can develop ICD with sufficient exposure. Allergic contact dermatitis (ACD) is an immune-mediated reaction that occurs in people who have become sensitised to a specific allergen. Common allergens include nickel (jewellery, belt buckles), fragrances, rubber chemicals (latex), hair dyes (paraphenylenediamine/PPD), preservatives in cosmetics (methylisothiazolinone), and epoxy resins. Once sensitised, even tiny amounts of the allergen can trigger a reaction.
Signs & Diagnosis
Both types of contact dermatitis cause redness, itching, swelling, vesicles (small blisters) and scaling. In acute cases, the rash is often well-demarcated and corresponds clearly to the area of contact. In chronic cases, the skin may become thickened, lichenified and deeply cracked — particularly on the hands. Diagnosis is clinical but distinguishing between irritant and allergic types is important for management.
Avoidance & Skin Care
The most important step in managing contact dermatitis is identifying and avoiding the causative substance. For irritant contact dermatitis, this means reducing wet work, using protective gloves (cotton-lined if there is latex allergy), and applying emollients regularly as a protective barrier. For allergic contact dermatitis, absolute avoidance of the identified allergen is essential. An evaluation of occupational exposures, personal care products and lifestyle habits is key to identifying the trigger — patch testing by a dermatologist can confirm the specific allergen. Read ingredient labels on cosmetics and toiletries carefully. A consistent skin care routine using emollients as soap substitutes helps to repair and protect the skin barrier. Do not use aqueous cream — it contains sodium lauryl sulphate (SLS) which worsens the skin barrier.