Allergic rhinitis, also known as hay fever, presents with symptoms of sneezing and a runny nose following exposure to an allergic trigger. Some individuals also experience allergic conjunctivitis, with itchy and watery eyes. Other symptoms can include an itchy nose or throat. Allergic rhinitis can have impact on sleep, loss of sense of taste or smell, development of a chronic cough, worsening of asthma severity and more frequent sinus infections.

Symptoms can occur with seasonal variation or all year round. This is usually due to the allergen trigger which can include grass, weeds and tree pollens, house dust mites, moulds and animals including cats and dogs.

Identification of the allergic cause can be made with allergen skin prick testing, and also with blood tests (allergen specific IgE testing). Skin prick testing provides immediate results at the consultation.

Allergic rhinitis is assessed to identify appropriate trigger avoidance, use of medications including intranasal corticosteroids and antihistamine therapy, and allergen immunotherapy (or desensitisation) to the allergen trigger. Rhinitis may be non-allergic in nature and in such cases medications still remain effective, and in some cases, surgery is considered.

Allergen immunotherapy is available in sublingual (tablet therapy) or subcutaneous (injection therapy). This involves supervised administration of an allergen preparation in a medical practice with the aim at reducing the allergic responses upon re-exposure. This is effective and often has long lasting benefits.

Food allergy is increasing in Australia with multiple individuals reporting having a history, particularly in children and those who have eczema. Food allergies occur due to an allergic immune response to a food that is harmless to most people. Common symptoms can include hives (urticaria), mouth itch, abdominal pain and diarrhea. More serious and life-threatening symptoms include swelling of the tongue or throat (angioedema), difficulty breathing and wheeze, or causing low blood pressure with dizziness or collapse.

Common causes in adults include peanuts, tree nuts and seafood. There is a wide range of possible allergens that can cause food allergies.

Some patients have a condition known as oral allergy syndrome, which occurs due to cross reactivity with environmental allergens such as tree, weed and grass pollens. In this situation, mouth itch and tingling and sometimes throat symptoms occur following exposure to eating raw fruits, vegetables and nuts.

Food allergies cause significant loss of quality of life, with food anxiety, dietary restriction and accidental exposures leading to reactions that may be life-threatening. Correct identification and diagnosis aids with providing patients with a safe approach with their diets and to provide emergency medications for severe anaphylaxis events with the provision of adrenaline auto-injector devices.

Food allergies can be diagnosed with thorough history taking and appropriate testing which includes allergen skin prick testing and blood tests. This identifies foods that may be implicated in previous reactions to guide dietary avoidance and to consider adrenaline auto-injectors. Some individuals may have food intolerances or another medical condition causing their symptoms. In those where a food allergy is unlikely, they may be considered for a in hospital graded food challenge under medical supervision.

Urticaria (hives) is a common condition which involves red, itchy lumps of the skin with swelling. The appearance looks similar to mosquito bites but may form large patches. Often urticaria can occur at multiple different body sites, and last for hours but often resolves within one day. Some patients with urticaria get angioedema, which is a deeper tissue swelling, which may affect areas such as the face, lips, tongue, or limbs.

Urticaria can develop for an number of reasons. These can include acute allergic reactions from foods, insects and medications. Viral infections can exacerbate urticaria, and in some individuals chronic urticaria can occur greater than 6 weeks and may persist for significant periods of time.

Patients with urticaria that does not respond to non-sedating antihistamines and other add on therapies may be considered for omalizumab therapy which is prescribed under strict PBS criteria.

Asthma is a common respiratory condition seen in approximately 1 in 9 Australians. It presents with variable airflow obstruction with symptoms of wheeze, chest tightness, difficulty breathing and cough. Symptoms can occur episodically and be specifically related to certain triggers such as viral infections, smoke exposure and allergen triggers including those that cause allergic rhinitis.

Some patients with asthma have difficult control despite optimal inhaler therapy. Adults affected with severe asthma can be considered for biological therapies available under the PBS that target certain inflammatory signals that are linked with airway inflammation. These medications significantly enhance quality of life and reduce exacerbation rates including need for hospital presentation.

Anaphylaxis is a multi-system allergic reaction that can be life threatening. This is a severe allergy that upon exposure with the allergen such as stinging insect venom, food allergens, medications and other reasons the body has a rapid onset and exaggerated response. This can cause difficulties with breathing through the upper airway including tongue and throat, the lower airway with symptoms similar to asthma, or low blood pressure leading to fainting and collapse.

Patients who are at risk of anaphylaxis are recommended to carry adrenaline auto-injector devices for emergency use and a written anaphylaxis action plan. Importantly, the culprit allergen must be strictly avoided to reduce the risk of further episodes. Accurate diagnosis is very important to accurately identify the cause and avoid unnecessary dietary and environmental restrictions.

Immune deficiencies can be caused from primary (genetic) and secondary reasons. Primary immune deficiencies are rare diseases. The have significant impairment in quality of life and often have a delayed diagnosis.

Immune deficiencies can be due to many causes including antibody deficiencies (reduced levels of antibodies or impaired responses to infections or vaccines), T cell defects (leading to risk of severe viral and fungal infections), complement proteins (increases risk of invasive bacterial infections) and disorders of neutrophils (increasing risk of atypical bacterial infections). Some patients may have immune dysregulation due to a genetic reason that increases the risk of recurrent unexplained fevers (also known as autoinflammatory disorders).

When to suspect an immune deficiency:

- Four or more infections requiring antibiotics within one year

- Recurring infections, or infections requiring prolonged antibiotic therapy

- Two or more severe bacterial infections

- Recurrent pneumonia

- Infection with an unusual localisation, or unusual pathogen

- Family history of primary immunodeficiency

Atopic dermatitis is an inflammatory skin condition with significant impairment in qualiy of life. In severe forms, this can lead to complications including superimposed bacterial infections and tendancy to have mutiple food allergies. Standard therapies including corticosteroid based topical treatments are the mainstay of treatment, however add on treatments are often indicated.