Seasonal Allergies in Pregnancy

Clinical Evaluation

Risk Factors

Exposure to the following allergens may trigger or worsen allergy symptoms

Pollen: Plants produce pollen as part of their reproductive cycle at different times throughout the year. Pollen is not dangerous, but their immune system might be sensitive to it, which can lead to allergy symptoms. Symptoms are triggered by airborne pollen, such as tree, grass or weed pollen. Get the daily pollen count at www.met.ie/forecasts/pollen.

Mould Spores: Moulds are a type of fungi which produce spores that can trigger an allergic reaction, particularly if the person has Asthma or COPD. Moulds often grow in damp environments, such as in a bathroom or kitchen.

House Dust Mites: House dust mites are tiny creatures that live in our homes, so it is difficult to completely avoid exposure to them.

Animal Dander: If the expecting mother has an allergy to pets, it is usually caused by saliva on the animal’s fur. They can also carry other allergens such as dust and pollen.

Signs²

• Itchy or watery eyes
• Itchy nose, mouth and throat
• Sneezing and coughing
• A blocked or runny nose

Symptoms²

• Headache
• Tiredness
• Shortness of breath.

Management & Advice

Minimising exposure to allergens will result in reduced levels of histamine in the body and in turn reduced allergy symptoms. If the patient is not sure what’s causing their symptoms, advise them to keep a diary of when they notice symptoms worsening. What time of day? Which month? Indoors or outdoors, day or night, at home or somewhere else? The most common allergens include pollen, mould spores, house dust mites and animal dander.

To help minimise exposure to pollen:

• Close windows
• Stay indoors during peak pollen times
• Shower after being outside
• Wipe down pets after being outside
• Wear wrap-around glasses
• Dry clothes inside

To help minimise exposure to Mould Spores:

• Keep windows open during the day
• Fix sources of damp and condensation i.e. drains
• Use anti-mould on sinks and baths monthly
• Remove clothes from dryer immediately
• Use an air purifier and dehumidifier

To help minimise exposure to House Dust Mites

• Vacuum with a HEPA Filter
• Damp dust regularly
• Change bedding weekly, and hot wash
• Use dust covers for pillow and mattress
• Remove carpets, cushions and soft toys from bedroom
• Consider an air purifier in bedroom

To help minimise exposure to Animal Dander:

• Wipe pets down if they’ve been outside
• If they develop a new allergy to their pet, advise them to try to restrict the rooms the pet is allowed into, and do not allow them in their bedroom

Non-pharmacological treatments

It is important to use non-pharmacological options in pregnancy where possible, particularly in the first trimester. Natural treatments can often be as effective as medication.

Saline nasal irrigation, is an effective way to directly cleanse the nasal cavity and it physically removes any allergens.⁶

Allergy cold therapy masks for 10 minutes can bring down inflammation around the eyes or the nasal cavity.

Nasal strips: Sleeping slightly upright and using nasal strips when sleeping may also reduce a stuffy nose.²

Pharmacological treatments

Intranasal corticosteroid sprays: Intranasal corticosteroid sprays are first-line treatment for rhinitis and are highly effective.⁷ The newer generation sprays including Fluticasone Propionate and Mometasone Furoate are safe in pregnancy.^2,7

Oral antihistamines: Oral antihistamines are the second-line treatment option, but are less effective.⁷ For example Chlorphenamine is suitable for use in pregnancy. However, it has a sedating effect, therefore Loratadine and Cetirizine are typically preferred.⁸

Immunotherapy: Maintenance of immunotherapy during pregnancy is safe. However, the initiation of allergen-specific immunotherapies should be avoided.⁹

 Rhino-light therapy: Phototherapy is well established for skin conditions and is now being used to manage rhinitis. Rhino-light is safe during pregnancy and is often the preferred treatment in pregnancy as it reduces the need for medication. Rhino-light uses 3 types of light to reduce histamine release from mast cells and destroys the white blood cells involved in the allergic response.

What to avoid

Avoid using nasal decongestants that contain Pseudoephedrine or Phenylephrine, as these can affect milk supply.

Intranasal antihistamines and oral corticosteroids should also be avoided in pregnancy. They are only used in cases of severe uncontrolled rhinitis.²

To reduce allergy risk for in babies

Healthy diet and lifestyle: Advise the mother to maintain a healthy diet and lifestyle, including taking pregnancy supplements and vitamins. Recent research has shown that a pregnancy diet rich in Vegetables, Yogurt, and Vitamin D can reduce allergy development in babies.¹⁰

Exposure to farm animals: Numerous trials have shown that maternal exposure to farm animals and hay during pregnancy results in increased numbers of cord blood Regulatory T cells (Treg), which reduces allergy risk in children, so advise expecting mothers to head out to the countryside when they can can.¹¹

Vaginal delivery and breastfeeding have a beneficial effect on baby’s gut bacteria and protect against allergy development, particularly Bifidobacterium Breve, a strain commonly found in breastfed infants and human milk.¹² Exposure to antibiotics in the third trimester or early life can have a significant impact on the allergy/asthma status of children.

Antibiotic use: A recent meta-analysis found that maternal antibiotic use might increase the risk of asthma/wheeze and eczema/atopic dermatitis, but not food allergy, in children.¹³ Nevertheless, the appropriate use of antibiotics during pregnancy is important, and healthcare professionals should be selective when prescribing antibiotics in pregnancy.