Common symptoms of allergy

A person may experience quite common everyday symptoms that in fact are caused by allergy. Even more serious conditions such as asthma attacks may also have and underlying allergic trigger. Here you can learn about a number of typical symptoms that often are a sign of allergy.

Eczema  |  Hay fever  |  Eye inflammation  |  Gastrointestinal conditions  |  Nettle rash/hives  |  Oral allergy syndrome  |  Asthma |  Anaphylactic reactions

Symptoms of allergy vary in complexity, severity and manifestation. With atopic allergies the effect of exposure to an allergen can be immediate. Symptoms can be mild or severe, varying from itchy eyes, to eczema, rhinitis, conjunctivitis, bronchoconstriction, vomiting and diarrhea and, in rare cases, anaphylaxis.

Chronic reactivities

Reactivities such as skin reactions (eczema) or asthma attacks may be caused by allergy. For example, an ongoing lung tissue inflammation can be the reason for an asthma attack seen after exposure to the offending allergen. Asthma attacks can also be brought about by events other than IgE-mediated reactions.

Manifestatations may vary

Manifestations of atopic disease vary considerably depending on the allergen involved, as well as the age of the allergic person. During infancy, allergies to food (especially egg and milk) are the most common. After the age of 3, most allergic children tolerate these foods, while allergy to inhalants becomes predominant. Specific IgE antibodies often precede allergy symptoms, but clinical symptoms catch up with time.

Read more about specific allergy symptoms:

Eczema

Symptoms

  • dry skin
  • itchy skin
  • nettle rash/hives (urticaria)
  • skin rash

Common triggers (allergens)

  • food (e.g. egg, milk, fish, wheat, peanut, soybean and hazelnut)
  • house dust mite
  • pets (e.g. cat, dog, guinea pig, rabbit)

Why do the symptoms occur?

Eczema can occur in connection with allergen exposure. It can also increase the sensitivity towards triggers because the natural skin barrier is damaged. Eczema in children has also been linked to an increased risk of developing rhinitis (e.g. hay fever) or asthma later in life.

Eczema in brief

Eczema is a condition that affects both children and adults. Most commonly it appears during the early years of childhood. Young children will often present with eczema on their cheeks, torso and/or joints of the arms and legs.

There is no available cure for eczema, but using a lotion is important. It is also important to investigate the cause of the eczema. With a clear diagnosis and good advice from your doctor, the patient will be better equipped to encounter and reverse some of the more unpleasant effects.

Hay fever (allergic rhinitis)

Symptoms

  • blocked-up nose
  • breathing through the mouth (only)
  • itchy nose
  • itchy throat/mouth/lips
  • itchy, red eyes and swollen eyelids
  • runny nose
  • sneezing
  • swelling of the mouth/airways
  • weeping eyes

Common triggers (allergens)

  • pollen (e.g tree, weed and grass)
  • house dust mites
  • cockroach
  • pets (e.g cat, dog, guinea pig, rabbit)
  • other animals (e.g. horse and bird)

Why do the symptoms occur?

Hay fever (allergic rhinitis) occurs when airborne allergens start an inflammation that triggers fluid production in the nose, sinuses, and in the eyes. Rhinitis is often seasonal, occurring during pollen seasons, but it can also be perennial, and persistent throughout the year.

Hay fever in brief

Hay fever or allergic rhinitis is an extremely common illness that is often mistaken for an ordinary cold. However, rhinitis may develop into more severe problems such as asthma. Recurring or drawn-out symptoms should always be investigated.

Eye inflammation

Symptoms

  • itchy, red eyes and swollen eyelids
  • weeping eyes

Common triggers (allergens)

  • pollen (e.g. tree, weed and grass)
  • house dust mites
  • cockroach
  • pets (e.g. cat, dog, guinea pig, rabbit)
  • other animals (e.g horse and bird)

Why do the symptoms occur?

Eye inflammation in connection with hay fever (allergic rhinitis) is often seasonal, occurring during pollen seasons, but it can also be perennial, and persistent throughout the year.

Eye inflammation in brief

Conjunctivitis is an inflammation of the eyeballs' outer layer which can occur as a consequence of exposure to allergens or because of an ordinary cold infection. Eye inflammation or conjunctivitis often occurs together with hay fever (allergic rhinitis).

Gastrointestinal conditions

Symptoms

  • diarrhoea
  • stomach pain
  • nausea and vomiting
  • weight loss

Common triggers (allergens)

Infants and toddlers (0-3 years)

  • egg
  • milk
  • wheat
  • soybean

Children and adults

  • egg
  • milk
  • shellfish
  • wheat
  • peanut
  • hazelnuts and other tree nuts
  • fruits and vegetables

Why do the symptoms occur?

The symptoms are closely associated with food intake. However, it can be difficult to make a proper diagnosis as there are several possible causes of gastrointestinal problems such as allergy, celiac disease or lactose intolerance.

Gastrointestinal problems in brief

Allergy can cause stomach/intestinal problems such as pain, diarrhoea and vomiting in adults as well as in children, even from the first year of life.

Nettle rash/hives (urticaria)

Symptoms

  • nettle rash/hives (urticaria)
  • skin rash

Common allergens

  • nuts
  • shellfish
  • eggs
  • milk

Why do the symptoms occur?

Hives could be both allergic and non-allergic and is very common. Allergy is a more common cause of hives in children than in adults.

In addition to allergy to foods or other substances like drugs, hives may be triggered by direct physical stimulation such as temperature extremes, water, sun, and physical exercise. Viral infections and stress can also cause an outbreak of hives.

Nettle rash/hives in brief

Nettle rash or hives (urticaria) are localized, pale, itchy, pink wheals (swellings) that can burn or sting. They may occur singularly or in groups on any part of the skin. Most episodes of hives disappear quickly in the space of a few days to a few weeks.

Oral allergy syndrome

Symptoms

  • itchy throat
  • itchy mouth
  • itchy lips

Common triggers (allergens)

  • fruits (e.g. apple, pear, cherry, peach, plum, apricot, kiwi)
  • vegetables (e.g. carrots, raw potato, celery)
  • nuts and legumes (e.g. hazelnut, cashew nut, walnut and almond, peanut, soybean)

Why do the symptoms occur?

Oral Allergy Syndrome (OAS) can occur in pollen allergic persons, when eating certain fruits, vegetables, nuts or beans. The symptom appears due to the fact that pollens contain proteins of similar structure to those present in this particular food. This is called a cross-reaction.

OAS is thus not a separate food allergy, but rather represents cross-reactivity between pollen and certain fruits and vegetables. It is usually limited to ingestion of only uncooked fruits and vegetables.

Oral allergy syndrome in brief

Oral allergy syndrome (OAS) is common among pollen allergic patients. It is normally a temporary and relatively mild condition characterised by swelling, redness and itching of the mouth area. Occasionally, also the eyes are affected.

Asthma

Symptoms

  • coughing
  • shortness of breath
  • wheezing and whistling breath

Common triggers (allergens)

  • pollen (e.g. tree, weed and grass)
  • house dust mites
  • cockroach
  • pets (e.g. cat and dog)
  • other animals (e.g. horse and bird)
  • foods

Why do the symptoms occur?

Asthma symptoms occur in connection with allergen exposure, exercise, cold air, dry air and in connection with airway infections. Other irritants, such as strong scents or cigarette smoke, can also trigger an asthmatic reaction.

Asthma in brief

Asthma is defined as persistent wheeze, often accompanied by whistling breath, shortness of breath and coughing, especially at night and in the mornings. It is the most common, chronic illness in early childhood, often triggered by allergy. 

Anaphylactic reactions 

Symptoms

Early mild symptoms can include

  • hives
  • tingling and itching around the mouth
  • swelling around the eyes and the mouth

Severe symptoms can include

  • itching, especially under the feet, the palms of the hands or scalp
  • tingling in the mouth
  • swelling in the mouth and throat
  • hypotension
  • abdominal pain
  • nausea and vomiting
  • shortness of breath
  • asthma symptoms
  • a deterioration of the general condition

Anaphylaxis is a reaction which affects different organs in the body, one at a time or several. Even if the symptoms initially can be experienced mildly, there is a risk that the symptoms rapidly turn into a life threatening condition and fast treatment is therefore very important. The situation is urgent if the person loses consciousness.

Common triggers (allergen)

  • peanuts
  • tree nuts, e.g hazel-, brazil-, wal- and cashews nuts
  • fish
  • soybean
  • seafood
  • milk
  • egg
  • seeds
  • fruits
  • drugs
  • bee and wasp venoms

Also other food can trigger severe reactions, depending on local eating habits.

Anaphylactic in brief

An anaphylactic reaction can also be called anaphylactic shock and is an acute life-threatening allergic reaction. The reaction usually occurs quickly, within 5-15 minutes and requires immediate care.

Food related anaphylaxis can be triggered when physical exercise is combined with intake of food that the person has an allergy to.

As in all diagnostic testing, the diagnosis is made by the physican based on both test results and the patient history.