Allergies

Many people suffer from an allergy to a particular food, substance or object which causes a variety of effects including skin rashes. There are many different types of skin allergies which are characterised by itching, dry or weeping skin which bleeds if scratched too violently.

You have probably heard of eczema but this is just one of many skin allergies. Others include contact dermatitis, hives and atopic dermatitis. If you have any of these then you will be only too familiar with the irritation and unpleasantness these allergies cause.

What is an allergy?

An allergy is your body’s reaction – extreme in cases – to a particular substance. Your body’s immune system perceives this as a threat and reacts by releasing antibodies to attack the potential threat. This causes a series of symptoms such as an itchy skin rash.

Basically, your immune system overreacts to a harmless substance and responds to this ‘threat’ by releasing chemicals which trigger these symptoms. The potential threat is known as an allergen.

Who is most at risk of a skin allergy?

The answer is anyone is capable of developing a skin allergy. It is no respecter of age or background and affects both young and old. Children are more likely to develop eczema whereas adults are prone to contact dermatitis.

Causes of skin allergies

There are several which include:

  • Metal, e.g. jewellery
  • Make up/cosmetics
  • Perfume
  • Household products, e.g. shampoo
  • Industrial products, e.g. floor polish
  • Rubber/latex
  • Poison ivy
  • Certain types of medication, e.g. topical creams (which are applied to the skin).

A patch test will determine the cause of your skin allergy.

Symptoms of a skin allergy

A skin rash is the most common symptom. This colour, shape and extent will depend upon the allergy, for example hives results in a red, itchy rash.

The rash may take the form of small raised bumps or blisters, is dry and flakes easily or red and weeping. The rash can develop as single patches or as clumps which are crusty and inflamed.

Other symptoms include:

  • Headaches
  • Flushed appearance
  • Dizziness
  • Swelling
  • Problems with sleeping (due to the rash)
  • Difficulty breathing – in extreme cases

Diagnosing skin allergies

The patch test (or skin test) is used to diagnose a skin allergy. This is conducted at your GP’s surgery or an allergy clinic and involves the placing of potential allergens onto your skin which are then left for a period of time.

Your skin is then examined to see if there has been a reaction. Another similar procedure is the skin prick test where your skin is pricked with a needle containing a tiny amount of the suspected allergen. If your skin becomes itchy, red and swollen then this confirms a diagnosis of an allergy.

A skin biopsy is another investigative test in which a small sample of skin is removed under a local anaesthetic and then sent to a laboratory for analysis.

A blood test is another useful diagnostic tool which measures the amount of antibodies in your blood. This is performed following contact with a suspected allergen.

This is measured on a 0 to 6 scale: a zero reading indicates no reaction but a 6 reading indicates a high degree of sensitivity. In other words, you have developed an allergy.

Treatment for a skin allergy

Your GP will prescribe a suitable course of treatment or in severe cases, will refer you to a dermatologist.

The dermatologist will recommend a combination of lifestyle and medications to treat your skin allergy. Lifestyle changes include avoiding (or minimising) contact with the allergen, wearing gloves if you have to handle an allergen and keeping the affected area clean. Avoid over washing, saunas, steam rooms and anything which is likely to dry out your skin.

Medications include topical creams – as long as this is not the allergen, antihistamines and antibiotics. Phototherapy can also help.

Find out more about these and other treatments in our dermatology treatments section.

Finally, not every skin allergy causes a rash. You may experience the itchiness but without a rash which can be the sign of an underlying condition. If this occurs then visit your GP.