Itchy skin is usually a reaction to something or a symptom of something else. It is characterised by the need to scratch or rub the skin – and sometimes this can be done unconsciously. In other cases it can be truly irritating and compulsive.

The itching can be acute – that is, it comes on quickly as the result of an allergy or something that has irritated the skin, like a bite.

In other case though it can be chronic and may indicate something as simple as dry skin or another underlying condition.

There are many different reasons for itchy skin. In many cases something – such as an allergen or irritant to the skin triggers the body to release histamines which result in the skin feeling itchy. In other cases there can be a simple reason- like dry skin, or the cause can be more complex, such as an underlying condition which makes the skin itchy.

Some causes of itchy skin include:

• Dry skin.
• Bites and stings.
• Allergies to food or something touched such as plants or latex.
• Certain medication can cause rashes and/or itchy skin and in some cases there can be an allergic reaction to certain medications.
• Eczema or dermatitis or other skin conditions.
• Infections like chicken pox, impetigo or measles.
• Fungal infections like tinea.
• Chronic renal (kidney) failure.
• Hepatitis and cirrhosis of the liver.
• Thyroid disease (over or under active thyroid).
• Iron deficiency.
• HIV infection.
• Parasitic infection like scabies.
• Type 2 diabetes.
• Multiple sclerosis.
• Haemochromatosis (too much iron).

In some cases anxiety can make itchs worse.

Sometimes the cause of itchy skin is obvious – a bite or sting or dry skin, but in other cases you may need to see a doctor to establish what the root cause is.

The doctor may look at your skin for signs of dryness or infection (such as a fungal, parasitic, bacterial or viral infection). He or she may ask questions about how it started, how long it’s been itchy for and how you’ve been feeling generally.

He or she may feel for swollen glands, and may order a variety of tests including urine and blood tests to look for other possible causes which could be related to an underlying condition. Skin samples to test for fungal causes may be taken as may a stool sample to test for parasites.

The treatment for itchy skin will depend on the cause.

If the cause is dry skin there are a few simple steps which can help relieve it which include:

• Try and keep your place cool and well humidified. Use a humidifier if necessary, especially over night.
• Dry not to wear clothes that irritate the skins or tight clothing.
• Avoid moisturisers or body products with fragrances, alcohol, wool, alkaline soap, or other potential allergens.
• When bathing (no more than once a day) use non-soap, low pH cleansers
• Wash gently making sure you rinse all the cleanser off and then gently pat the skin dry.
• Once dry apply a non-fragranced moisturiser to the skin. It can also help to put it on again before bedtime.
• Drink plenty of fluids to maintain good hydration.

If the cause is a bite, sting or allergic reaction, an antihistamine tablet such as those taken for hay fever can help, or applying an antihistamine cream.

If dermatitis of eczema is the problem then regular moisturising can help and corticosteroid creams may be prescribed.

If the cause is a virus like chicken pox the itching will go away by itself but applying calamine lotion may relieve the need to scratch.

If a fungal infection is the problem then applying an antifungal cream can stop the itching.

If the cause is an underlying condition, treating that condition may relieve the itching.

If the cause is a medication you’ve recently started taking, it’s best to talk to your doctor before you stop taking it so he or she can advise on a suitable alternative.

As dry skin is a common cause of itchy skin, there are some simple steps that can be followed to help reduce the need to scratch. These include:

• Use a humidifier if you live in a dry area.
• Apply a hypoallergenic and an unperfumed moisturiser after bathing and before bed time. Those that contain oatmeal can be soothing, especially for dermatitis. Products containing petroleum jelly can work well too.
• Drink plenty of fluids (water and juice) to keep hydrated.
• Use soaps that are ‘soap free’ and are pH balanced so they don’t dry the skin out further. Try not to use harsh cleaning chemicals with a high alkaline level – and use gloves if you do have to use them.
• Identify and avoid allergens that can trigger itchy skin – such as latex gloves or condoms.
• Don’t bathe too often – once a day is enough and only use the soap-free or pH balanced soaps on your armpits or areas that need cleaning. Water is usually enough for the rest of the skin.
• Keep the bath or shower cooler rather than too hot as the heat can make the skin itchier.
• Getting a bit of sun on the skin can sometimes help.
• Keeping areas between the toes and the groin area dry can reduce the risk of fungal infections recurring. Wearing thongs around change rooms and pool areas reduced the risk of fungal infections.
• If you have a fungal, parasitic, viral or bacterial skin infection – do not share towels or clothing as you could pass it on to someone else.
• Hydrocortisone creams may help in some cases but do not use them on your face or genital areas unless instructed to by your doctor.
• If you use a bath oil, be careful, as it can make the bath or shower slippery and you may fall over.

MD Consult: Walsh: Palliative Medicine, 1st ed

American Academy of Family Physicians 2008