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What’s that rash?: with pictures

Heat rash on body
What's that rash?

Have you ever Googled, ‘what’s that rash?’ You may have been looking for yourself, your child or a ‘friend’.

Chances are you’ve had a rash or two in your lifetime. What is a rash? A rash is a temporary flare-up on the skin. It usually appears as red spots or reddening. It can sometimes be dry, scaly or itchy.

Your skin is actually covered in trillions of bugs, these are called microorganisms and together they make up your skin microbiome. When they are balanced and happy so is your skin. Rash conditions like eczema and dermatitis are caused when your skin microbiome is out of balance. Find out more about your skin microbiome by listening to our podcast: My Amazing Body.

There are many types of rashes, including eczema, hives, and heat rash. Some rashes can be temporary, or they might be a chronic condition. Sometimes rashes can be a sign of a serious illness, like measles, so it’s important you seek medical advice if you are concerned about a rash.

We’ve listed some common rashes, their symptoms and how you can treat them. The rashes we mention usually occur on your face and sometimes other parts of the body. If you’ve got a rash ‘downstairs’ it could be a symptom of an STI and we recommend you talk with your GP or get a sexual health check.

Eczema

Eczema on arm

Eczema is a skin condition that affects children and adults. It is more common in children, in fact, 66 percent of eczema sufferers are diagnosed before aged two. They will usually grow out of eczema by adolescence. It can also be called atopic eczema, atopic dermatitis and allergic eczema.

We don’t really know exactly what causes eczema, but we do know that it can sometimes be genetic. One gene linked to eczema is called filaggrin and people who get eczema often have a defect which reduces their skins ability to repair itself after injury. It also allows allergens to enter the deeper layers of the skin. People who have eczema may also have other conditions like hay fever or asthma.

Some triggers that cause and make eczema worse include:

  • dry skin
  • scratching the affected area
  • viral or bacterial infections
  • chemicals from swimming pools
  • sand, especially from sandpits
  • some types of carpet or grass
  • animals or house dust mites
  • allergens that you can breathe in, such as pollen
  • artificial colours and preservatives
  • perfumes, soap and chemicals
  • woollen or synthetic fabrics
  • heat or very hot rooms
  • stress

Eczema causes very itchy, scaly, red patches of skin, usually on cheeks, in elbow creases and behind the knees.

Your doctor will be able to diagnose you with eczema and advise a suitable treatment plan. The most effect way to relieve symptoms and treat eczema is to keep the skin well moisturised by using a non-perfumed moisturiser on your skin every day.  It’s also best to avoid itching the area to reduce breaking the skin which can increase the chance of infection.

The skin has special cells that have an immune function. Eczema causes a breakdown in the skin’s barrier function. Sometimes, children with eczema are more prone to developing allergies. Foreign proteins make their way through the damaged skin and activate the immune cells.

For this reason, it is important not to use creams containing food ingredients. e.g. oats, goats’ milk, almond oil. Using creams containing food ingredients can cause an allergy to that food to be developed.

Contact dermatitis

Contact dermatitis

Contact dermatitis is inflammation of the skin. There are two types of contact dermatitis, which occurs when your skin touches something that makes it red and inflamed. Allergic contact dermatitis is when your skin becomes inflamed after coming into contact with an allergen, like plants. If your skin is exposed to an irritant, like cosmetics, for a long period of time this is called irritant contact dermatitis.

Contact dermatitis can cause the skin to become:

  • cracked
  • red
  • blistered
  • thickened
  • dry
  • itchy

The rash should clear slowly if you avoid the substance that is causing the irritation or reaction. You should see a doctor if your rash is uncomfortable or doesn’t clear up. They will be able to assist you with treatment and help find the allergen or irritant.

Heat rash

Heat Rash

Heat rash often occurs during summer and is usually harmless. It’s also known as prickly heat or miliaria. Heat rash is caused by a blockage and inflammation of your sweat ducts.

Symptoms can last 2-3 days and can include, tiny red spots or blisters, an itchy or prickling sensation, redness or mild swelling of the area. It is more common in sweaty areas of the body. The armpits, back, under the breast, chest, groin or crooks of your elbows and knees are all areas that can be affected.

To reduce the risk of heat rash you should stay cool during the hotter months, by drinking water regularly, wearing light clothing and staying out of the heat. Heat rash can sometimes be the first sign of a heat-related conditions, like heat stroke or exhaustion, which require urgent attention.

Heat rash will usually go away by itself. You should see you doctor if the rash gets worse or lasts more than 3 days. If the blisters become infected with yellow or green pus, if you have a fever or are feeling generally unwell you should see your doctor.

Hives

Hives on body

Hives, also known as urticaria or nettle rash, is a skin rash that occurs when the body produces histamine. Histamine is a protein your body uses to fight off viruses and bacteria but when you get hives, your body might be reacting to an irritant.

Hives symptoms include a raised bumpy red rash. The bumps can sometimes look more like your normal skin colour and can be quite itchy. The trigger for hives is sometimes unknown but can be caused by an allergic reaction, medication or an infection.

It can sometime take days or weeks for hives to develop but true hives can last just a couple of hours or up to 6 weeks. You should see your doctor is the rash lasts longer that 6 weeks or if you are concerned.

Hives are usually harmless, but sometimes they might be a sign of anaphylaxis. Anaphylaxis requires urgent medical attention. If you or your child is having difficulty breathing, seems to have a swollen tongue or throat or has collapsed, phone Triple Zero (000) for an ambulance immediately.

Rosacea

Rosacea

Rosacea, or acne rosacea, is a non-contagious, common skin inflammation that only affects the face. It causes redness, flushing and sometime pimples on your face, though it is not the same as acne.

The first signs of rosacea can include frequent flushing or blushing of the skin and it usually appears between the ages of 30 and 50 years old. The cause is unknown and there is no cure, and unfortunately symptoms get worse as you age.

Symptoms of rosacea:

  • frequent blushing, flushing or redness on your cheek, nose, chin or forehead
  • persistent redness that looks similar to a sunburn that does not go away
  • small visible blood vessels on your face
  • bumps or pimples on your face that might sting or burn
  • red or irritated eyes or swollen eyelids

Some people’s rosacea can also be triggered by exposure to sun, hot weather, spicy foods, exercise or certain medications and skincare products. Talk to your doctor or a skin specialist for recommendations to control the symptoms.

If you are concerned about a rash or it is associated with a severe headache, neck stiffness, fever or vomiting and nausea you should see your doctor or call 13 HEALTH (13 43 25 84) for medical advice.

More information

Health Direct

Raising Children

Eczema Association of Australia

My Amazing Body Podcast - The Skin Microbiome

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Last updated: 9 September 2020