What is contact dermatitis?

Contact dermatitis is when your skin becomes inflamed because of something that has touched it. Dermatitis can make your skin dry, red, painful and itchy. It can also cause your skin to split and crack, peel, feel like it’s stinging or burning, and sometimes blister.

Contact dermatitis mostly affects people’s hands but can also affect their arms and face. If untreated it can sometimes spread to other parts of the body and can become more difficult to treat. 

It can take many months for the skin to heal.

Contact dermatitis is not infectious and you cannot pass it on to others. However, broken skin and sores can also make it more likely for you to get an infection.

Types of contact dermatitis

There are three main types of contact dermatitis: 

• irritant contact dermatitis, 
• allergic contact dermatitis, and 
• contact urticaria. 

You can have multiple types of contact dermatitis at the same time. 

Irritant contact dermatitis:

• is the most common kind of contact dermatitis
• happens when the skin’s natural barrier is irritated or damaged, usually by repeated exposure to an irritant or from exposure over a long period of time, and
• can also be caused by repeated wetting and drying of the skin.

Allergic contact dermatitis:

• is when your skin has an allergic reaction to a material (known as an allergen)
• can happen after many years of exposure
• can also happen even after a very small amount of contact, or from trace amounts of an allergen
• can be a delayed reaction, happening up to 72 hours after contact 
• can be more likely to happen if the skin is already damaged by irritant contact dermatitis, and
• is likely to be a lifelong allergy once it has developed. 

Contact urticaria:

• is the rarest kind of contact dermatitis
• is a fast (10 to 30 minutes) allergic response that can also cause hay fever-like symptoms or asthma
• can cause hives on the skin 
• sometimes causes anaphylaxis, a severe allergic reaction that can be life threatening, and
• can be caused by certain animal and plant products, including latex gloves.

Risks of contact dermatitis at the workplace

Work-related contact dermatitis is where you get contact dermatitis from something you are exposed to at work. Chemicals and wet work (work in water or with wet things) are the main causes of contact dermatitis at the workplace.

Irritants and allergens

Some things used in the workplace are known to cause contact dermatitis. These include both chemicals and ‘natural’ things such as fruit, flour and wood dust. Some products that are designed to keep hands clean and healthy, like handwash and moisturisers, can also contain chemicals that can cause contact dermatitis.

Some workers may not be affected  at all while others have a strong reaction. Sweating, heat and dust can make contact dermatitis worse.

Severe contact dermatitis caused by strong acids (e.g. hydrochloric acid) or strong alkalis (e.g. bleach) are known as chemical burns. 

Some things known to cause irritant contact dermatitis are:

• acids and alkalis (e.g. lemon juice, wet cement)
• oils and cooling fluids 
• solvents (e.g. thinners, nail polish remover), and
• petroleum products (e.g. petrol, kerosene).

Image 1. Irritant contact dermatitis in an abattoir worker. Image source: Atlas of Dermatology 

 

Image 2. Irritant contact dermatitis in a farmer. Image source: Atlas of Dermatology

Some things known to cause allergic contact dermatitis are:

• epoxy resins (used in glues, marine paint and surface coatings)
• hair dye, perm solution and hair bleach
• glue
• synthetic rubber, and
• preservatives.

Some chemicals known to cause contact dermatitis may come with a warning. The label or safety data sheet say something as ‘may cause an allergic skin reaction’ or ‘causes skin irritation’.

 

Image 3. Allergic contact dermatitis in a painter from isothiazolinones (MC1/M1) in paint. Image source: Atlas of Dermatology
 

 

Image 4. Allergic contact dermatitis caused by garlic. Image source: Atlas of Dermatology

 

Wet work

Your skin can be damaged if it is often wet or wet for a long time. Wet work can lead to contact dermatitis. 

Wet work is: 

• where any part of your body is in water or other liquids for longer than 2 hours a shift 
• where any part of your body is in waterproof personal protective equipment (PPE, like gloves) for longer than 2 hours a shift
• handling wet things for longer than 2 hours a shift, or
• washing your hands more than 20 times a shift.

Contact dermatitis caused by wet work is particularly common in cleaners, healthcare workers, food handlers and hairdressers.

Other risk factors

Some workplaces have environmental conditions that are more likely to cause contact dermatitis. These include:

• high levels of dust or airborne fibres 
• friction from handling rough surfaces or using tools that rub the skin
• dry air
• very hot or very cold temperatures, or
• frequent handwashing or use of hand sanitiser 
   

Wet work is: 

• where any part of your body is in water or other liquids for longer than 2 hours a shift 
• where any part of your body is in waterproof personal protective equipment (PPE, like gloves) for longer than 2 hours a shift
• handling wet things for longer than 2 hours a shift, or
• washing your hands more than 20 times a shift.

Contact dermatitis caused by wet work is particularly common in cleaners, healthcare workers, food handlers and hairdressers.

Other risk factors

Some workplaces have environmental conditions that are more likely to cause contact dermatitis. These include:

• high levels of dust or airborne fibres 
• friction from handling rough surfaces or using tools that rub the skin
• dry air
• very hot or very cold temperatures, or
• frequent handwashing or use of hand sanitiser