Atopic dermatitis triggers include:1,8

·       soaps, detergents and fragrances

·       environmental conditions (eg cold/dry weather, dampness, extreme heat)

·       environmental allergens (eg house dust mite droppings, pet fur/animal dander, pollen, mould spores)

·       food allergens (eg cow's milk, eggs, peanuts, soya, wheat)

·       fabrics (wool, synthetics)

·       hormonal changes (eg in women before the period or during pregnancy)

·       teething

·       skin infections.

Contact dermatitis shares some common triggers, including irritants such as detergents, but also diluted acids or alkalis, solvents, metallic salts, cement, and resins. These can be an occupational risk for some people, including nurses, hairdressers, cleaners, chefs, or construction workers.1

Allergic contact dermatitis can also arise due to allergens such as:1

·       nickel or cobalt in jewellery or clothing studs/clasps/buckles

·       rubber/latex

·       dyes/resins in clothing/shoes

·       perfumes/preservatives found in cosmetics, toiletries, or topical medicines.

Para-phenylenediamine (PPD) found in hair dyes and henna products is a skin sensitiser and the commonest cause of hair dye contact dermatitis.9 Methylisothiazolinone (MI), an antimicrobial and preservative, has been associated with a significant rise in contact dermatitis. It was increasingly used in household products and toiletries, including wet wipes, but recent legislation means it should not be used in leave-on products.10,11

Several plants are implicated in contact dermatitis, including: primula, chrysanthemums, daffodils, tulips, sunflowers, ranunculus (buttercup family), mustard, borage and spurge/euphorbia.1,8