Skin conditions – Eczema, dermatitis, psoriasis

Skin conditions – Eczema, dermatitis, psoriasis

Often it’s difficult for someone to know what skin condition they have, because they all look and feel so similar. Red, dry, itchy. So why bother knowing what they are?

Because the long term management of all the different skin conditions (and there are thousands) can be quite different. But the most commonly seen skin conditions in general practice is eczema and dermatitis, so read on for more information and some great tips to help get them under control.

If you’re on a internet surfing session, check out Dermnet NZ or the Australian College of Dermatology A-Z of skin. Don’t be too tempted to pattern match, as I said there’s a lot of red itchy skin conditions out there.


The terms eczema and dermatitis are often used interchangeably, which confuses a lot of people. Dermatitis is inflammation of the skin, specifically the epidermis layer. Eczema is another name for the same thing, though it’s common that people refer to eczema when they mean atopic dermatitis.

And to complicate things further, the duration and site of the dermatitis often gives it different names.

Atopic dermatitis

This is the type of dermatitis often seen in younger children and babies and there is a h2 inherited component. Often a parent or sibling also has either dermatitis, asthma, or hay fever (allergic rhinitis) or all three. It’s fairly uncommon in children under 4 months old, although there are other similar looking skin conditions that can occur at this age.

The skin becomes easily irritated, usually involving the cheeks in very young children, the outside of joints (front of knees, backs of elbows) in toddlers and preschoolers, later involving the inside of joints in children as they age (inside the front of the elbow or behind the knees).

As adults get older the eczema can become very localised and very thick, sometimes causing darkening of the skin.

Irritant contact dermatitis

This form of dermatitis is caused by either physical or chemical irritation to the skin, causing damage faster than it can be repaired.
The commonest irritants are water, soaps, detergents, solvents, acids, adhesives, and friction.

Commonly found in professions where a lot of contact with chemicals or regular hand washing occurs like hairdressers, medical staff, food preparation, nail technicians and factory workers.

Young children learning to eat can have irritation from dribble that comes out the mouth onto the skin, or from a nappy that might have been left on too long whilst full. Also people who lick their lips will get irritation of the surrounding skin.

One thing not to forget is that cosmetics can cause an irritant contact dermatitis, even after prolonged use with no issues. In patients with rosacea for example, as the underlying condition worsens the cosmetics can irritate further.

Allergic contact dermatitis

While it may seem similar to irritant contact dermatitis, allergic contact dermatitis differs in its mechanism and onset.

It’s a delayed type of hypersensitivity reaction, causing a rash about 48-72 hours after contact with a specific allergen. It is different to getting a rash after ingestion of an allergen, and can develop to something you’ve been in contact with all your life.

Common reactions are to adhesive bandages, watch bands, certain gloves, cosmetics, acrylate glue from nail cosmetics, and nickel in jewellery.

Sometimes an allergic reaction only occurs after contact has been made AND the area gets exposed to UV light (sunlight). This is called photo-contact dermatitis

Discoid eczema (nummular dermatitis)

Triggered off by trauma to the skin, like injuries or insect bites, discoid eczema is so called because of its round or oval shape. It can also be triggered by generally dry skin, contact dermatitis, or other skin issues.

It is often mistaken for ringworm because of the similar shape and appearance, and if there are only one or two lesions some scrapings might need to be taken to clarify the diagnosis.

It appears to affect males more than females, but affects children and adults equally.

Dandruff and Seborrhoeic Dermatitis

Seborrhoeic dermatitis is a very common type of eczema/dermatitis that affects the gland rich areas of the scalp, face and trunk. As such people find inside the hair, beard and armpits can become quite inflamed.

Dandruff is the name we give to the uninflamed version. This is also called pityriasis capitis. This produces flakes of dry skin in the hair bearing areas of the scalp.

We’re not completely sure what causes it, but can be associated with a proliferation of Malassezia, a type of yeast that usually resides on the skin.

Infantile seborrhoeic dermatitis (or cradle cap) usually occurs in babies younger than 3 months old, but resolves by 12 months of age.

Adult seborrhoeic dermatitis starts in late teenage years and is associated with;

  • Oily skin
  • Family history
  • Lack of sleep or stressful events
  • Immunosuppression: People with organ transplants or immunodeficiency syndromes
  • Neurological conditions

Adults typically experience the following;

  • Worsening in winter – improving in summer
  • Minimal itching most of the time
  • Combination facial skin (oily and dry)
  • Scaly red eyelids (blepharitis)
  • Flakey patches on the hairline or anterior chest
  • Rash in armpits, under the breasts, in the groin folds or genital creases
  • Inflamed hair follicles on the cheeks and upper body

Otitis externa (dermatitis)

Otitis externa means inflammation of the external ear canal. The passage between the outside world and the ear drum.

Usually we see these as infections following an injury (scratches from fingernails) or use of cotton buds to clean, or following swimming where water gets trapped in the canal and irritates.

However it is possible to get dermatitis in the ear also, for people that suffer from any of the above types of dermatitis.

Symptoms include itchy ears, dry skin coming out of the ear canal, sometimes crusting and an ooze, and pain.

Other forms of dermatitis

There’s also venous eczema associated with varicose veins, gravitational eczema associated with swollen legs, and a Mayerson naevus which is eczema that involves moles.

Treatment strategies

Although some of the specific types of dermatitis require specific treatment, there are general principles that all follow that will prevent recurrence and improve the symptoms.

Avoidance of triggers

If you know that springtime brings about a flare up in your asthma, hayfever AND your dermatitis, then being prepared will help avoid the flareup being worse. Using a daily antihistamine and vacuuming regularly can make things better.

If you have allergic contact dermatitis then make sure you don’t allow yourself to come into contact with those triggers.


Avoid taking baths too often. The prolonged exposure to warm water can cause the skin to dry out after and cause microtears making it easy for the skin to become irritated. Showers are better, and even then the shower should be as cool and short as you can tolerate.

For example, wet the body, turn the water off, use a non soap cleanser (such as QV wash or Cetaphil), then turn the water on to rinse, and voila, end of shower.


Clothes that are coarse and irritating can trigger eczema. Things like wool, or clothing that doesn’t breathe are often worse.

Moisturising and emollients

Keeping the skin hydrated is essential, and the use of a non irritating moisturiser daily is very helpful in preventing flares. To simplify this step using a wash that is moisturising can help. Again QV wash, Cetaphil wash are some good non irritating products. You can ask your pharmacist for help selecting an appropriate wash.

Sometimes when the skin is very dry you might need a h2er emollient, something quite thick that really holds the moisture in. Dermeze and urederm 10% are both very potent, without added fragrances.

Topical steroids

Although there is a lot of fear about prolonged topical steroid usage, it is often the opposite which causes the most problems – ineffective usage or inadequate treatment. Steroids come in varying strengths from very mild over the counter steroids typically for the face, to very h2 steroids in a fatty base for persisting thick eczema.

This is important to get right, so chat to your doctor and make sure you are clear on how to use it, how much to apply, how often and for how long.

Non steroid anti-inflammatory cream

There are new creams that work very well for eczema/dermatitis without the side effects of steroids, but are quite expensive. They are cheaper on the PBS for patients suffering eczema around the eyes, or those who have conditions where steroid usage can make things worse. It is possible to get this on a private prescription if your doctor feels there is a benefit in it.

Bleach baths

For patients with eczema and dermatitis all over the skin, where colonisation with staphylococcus aureus is an issue, then reducing the load of bacteria improves the recurrence of flares.

Fill up a bathtub by measuring how many 10L buckets it takes to fill. Place the bucket under the tap, and pour it into the bath keeping count.

Then add

  • 1-2 capfuls of bathoil
  • 100g (1/3cup) of pool salt for each 10L of water
  • 12mL of White King Bleach (4% bleach) per 10L of water

This is then performed for;

  • Every day for 1 month
  • Three times a week for 1 month
  • Once a week for 1 month
  • Stop when the eczema settles

You can either recommence, or increase the frequency if the eczema begins to flare again.

If you are worried that your eczema isn’t being well controlled, or you would like to know ways to improve, book in with your doctor at GS Health.

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