Allergy Ireland's Dr Iseult Sheehan features in the Irish Medical Times in June 2021.
Pregnancy is a wonderful and exciting time. However, it can be complicated by physical and emotional changes which can be daunting. A common debilitating condition in pregnancy is rhinitis.
Rhinitis can develop in pregnancy or may be an exacerbation of a pre-existing rhinitis. The aetiology is multifactorial, but can be driven by allergy, non-allergic triggers, or infection.(1) In addition, it can occur simply as a result of physiological changes in pregnancy referred to as ‘pregnancy rhinitis’.
Research suggests that rhinitis does not directly affect pregnancy outcomes. Nevertheless uncontrolled rhinitis can indirectly affect pregnancy by impacting on sleep, stress, asthma control and quality of life.(2,3)
Symptoms and complications
Rhinitis is characterised by rhinorrhoea, nasal congestion and a post-nasal drip. Fatigue remains a significant symptom and can have a considerable impact on quality of life.(1) In addition, if there is an allergy trigger, sneezing and pruritis may be present. When untreated there is an increased risk of acute bacterial sinusitis.
Alongside these problematic nasal symptoms, patients risk experiencing complications such as mouth breathing – with resultant reduced quality of sleep and snoring. This further impacts on fatigue and may precipitate mood changes. Snoring in pregnancy is associated with increased risk of gestational hypertension, preeclampsia and intrauterine growth retardation. Furthermore, pregnancy rhinitis may induce the development of sleep apnoea in those predisposed to this condition.(4)
Asthma is challenging for up to 8% of pregnant women and can affect the outcome of pregnancy.(5) Based on the ‘united airways’ disease approach we know that 90 per cent of asthmatics have allergic rhinitis and 30-40 per cent of those with allergic rhinitis have asthma. Moreover, the treatment of nasal inflammation in asthmatics has been shown to improve outcomes. Uncontrolled rhinitis may in fact exacerbate co-existing asthma during pregnancy.(3) Co-existing rhinitis and asthma in pregnancy have been shown to reduce asthma control, reduce quality of life and increase anxiety. (2)
Pregnancy rhinitis affects 20-30 per cent of pregnancies and can occur at any gestational week.It is defined as nasal symptoms during pregnancy lasting six or more weeks with no other signs of respiratory tract infection and no known allergic cause. Furthermore, these symptoms can be distinguished from other forms of rhinitis as they completely disappear within the first two weeks after delivery.(3,4)
The pathogenesis of pregnancy rhinitis is complex and poorly understood. During pregnancy the nasal mucosa becomes hyperemic and oedematous. There may be glandular hyperactivity and increased phagocytic activity.(3)
It was always attributed to changes in oestrogen levels although there is little evidence to support this. It is suspected placental growth hormone plays a role. Despite this rhinitis patients have been shown to have comparatively higher levels of oestrogen and insulin-like growth factor-1 during the third trimester.(1)
Smoking may be a risk factor for developing pregnancy rhinitis as is sensitisation to dust mites.(4) Nevertheless these patients are not any more likely to have asthma or allergic rhinitis though these conditions can co-exist.
Effect of Pregnancy on Pre-existing Rhinitis
Pre-existing rhinitis can improve, worsen or remain the same during pregnancy. These trends are similar to those with pre-existing asthma during pregnancy.(3) It is always important to exclude infection and excessive decongestant use causing rhinitis medicamentosa.
Allergic rhino-conjunctivitis affects at least 400 million people worldwide and the prevalence within Europe is between 17 and 29 per cent.(6) The UK has a prevalence of 26 per cent and Ireland is likely to be similar to this. As such, it is no surprise that allergic rhinitis is common in pregnancy. The prominence of nasal and ocular pruritis and sneezing is usually an indication of an allergy to house dust mite, grass or tree pollen, mould or animal dander.
Non-allergic rhinitis affects a minority of this cohort but can still result in significant symptoms. It is a hyperreactive response to a stimulus such as irritants and air pollutants, stress, spicy food and alcohol, medications and even atmospheric changes (temperature or barometric pressure). It can be difficult to ascertain the trigger.
Effective management of rhinitis is vital to reduce the need for medications during pregnancy such as antibiotics or oral corticosteroids while also lessening the likelihood of sinus infection.
It is important to use non pharmacological options in pregnancy where possible. Where the patient has allergic rhinitis allergen avoidance should be encouraged.
Nasal congestion worsens on lying supine. Elevating the head of the bed at a 30-45 degree angle is considered more effective than additional pillows.(3)
Frequent exercise can improve nasal congestion by acting as a physiological nasal vasoconstrictor.(3)
Saline nasal irrigation or nasal sprays are safe in pregnancy (7) and are an effective way to directly cleanse the nasal cavity with the resultant reduction of mucus, inflammatory mediators and bacterial burden. It has also been shown to improve mucociliary function.
Phototherapy is well established for skin conditions and is now being used within the nasal cavity to manage allergic, vasomotor and pregnancy rhinitis. Endonasal phototherapy (Rhinolight) uses UV-A (25%), UV-B (< 5 per cent) and visible light (70 per cent) to induce a local immunosuppressive effect by inhibiting allergen induced histamine release from mast cells and inducing apoptosis of T lymphocytes and eosinophils.(8) It is particularly useful in pregnancy in limiting the need for pharmacological treatment.
Where possible all medications should be avoided during the first trimester. Prior to prescribing medication in pregnancy the benefits and risks to the mother and foetus should be considered. Most medications cross the placenta so the minimal effective dose should always be used.
Topical medications are considered first-line to minimise systemic absorption. These include topical mast cell stabilisers and intranasal corticosteroids. Sodium cromoglicate eye drops are effective for ocular symptoms in allergic rhinitis and have a good safety profile suggesting no adverse effects to the foetus.(9)
To minimise systemic absorption further, digital pressure can be applied to the lacrimal punctum for 1-2 minutes following application of the eye drops.(9)
Intranasal corticosteroid sprays are highly effective at reducing symptoms of rhinitis. The safety profile of corticosteroid nasal sprays is based on data from corticosteroid inhalers used in asthma during pregnancy.This is particularly reassuring as inhalers deliver higher doses than nasal sprays.The newer generation sprays which carry a low bioavailability are recommended. he sprays of choice include Fluticasone propionate and Mometasone furoate. (1,3) There is minimal data regarding the use of intranasal antihistamine although low systemic exposure is likely. Despite this, it is generally avoided in pregnancy.
Oral antihistamines are the second-line treatment option but are less effective at relieving nasal congestion. The newer second-generation antihistamines are recommended as they are less sedating and have fewer cholinergic side effects. Both Cetirizine and Loratadine have human pregnancy data with no evidence of increased risk to the foetus.(1,3,9,10) The other second-generation antihistamines rely on animal based studies alone.(9) Chlorphenamine is the only first-generation antihistamine suitable for use in pregnancy based on decades of animal and human data which has been reassuring.(9) However, it has sedating side effects and there is increased risk of cognitive impairment so it is very rarely used in pregnancy.
If watery rhinorrhoea persists, an intranasal anti-cholinergic can be considered such as Ipratropium bromide. The reassuring safety profile relies on data involving the use of inhaled Ipratropium bromide in asthma management during pregnancy.(1,9)
Leukotriene receptor antagonists show good human gestational safety data when used for asthma in pregnancy.(3,9) However, intranasal corticosteroids are more effective at managing nasal congestion and so Montelukast should only be used in exceptional circumstances where there would be a substantial benefit to the mother.
Oral/Intranasal decongestants and oral corticosteroids should be avoided in pregnancy. They are only used in cases of severe uncontrolled rhinitis where the benefit of rapid symptom relief is worth the potential risk to the foetus.(3,9)
Immunotherapy in Pregnancy
Sublingual Immunotherapy (SLIT) to grass pollen, house dust mite and tree pollen are treatment options for allergic rhinitis. There is limited data available but animal studies show no obvious increased risk to the foetus. In addition a study in 2012 involving 185 pregnancies found SLIT to be safe when used in pregnancy.(11) However, it is advised not to initiate SLIT during pregnancy. If pregnancy occurs during the three-year treatment, evaluation of the patient is necessary to determine whether to continue during the pregnancy.(1,3) In particular lung function and pre-existing asthma need to be monitored closely. (3,11)
Dr Iseult Sheehan
Clinical Director, Allergy Ireland,
MICGP, FRACGP, MB BAO, BCh, LRCP&SI, BA (Hons) Biochemistry and Immunology
- Scadding GK, Kariyawasam HH, Scadding G, et al. BSACI guideline for the diagnosis and management of allergic and non-allergic rhinitis (Revised Edition 2017; First edition 2007). Clin Exp Allergy 2017; 47(7): 856-89.
- Powell H, Murphy VE, Hensley MJ, Giles W, Clifton VL, Gibson PG. Rhinitis in pregnant women with asthma is associated with poorer asthma control and quality of life. J Asthma 2015; 52(10): 1023-30.
- Schatz M. Recognition and management of allergic disease during pregnancy. UpToDate. Last updated: Sept 2020. Accessed via: https://www.uptodate.com/contents/recognition-and-management-of-allergic-disease-during-pregnancy. Last accessed on: May 20, 2021.
- Ellegard EK. Clinical and pathogenetic characteristics of pregnancy rhinitis. Clin Rev Allergy Immunol 2004; 26(3): 149-59.
- Weinberger, S.E. et al. Asthma in pregnancy: Clinical course and physiologic changes. UpToDate. Late Updated March 2020. Accessed via: https://www.uptodate.com/contents/asthma-in-pregnancy-clinical-course-and-physiologic-changes. Last Accessed: May 20, 2021.
- Bauchau V, Durham SR. Prevalence and rate of diagnosis of allergic rhinitis in Europe. European Respiratory Journal 2004; 24(5): 758.
- Garavello W, Somigliana E, Acaia B, Gaini L, Pignataro L, Gaini RM. Nasal lavage in pregnant women with seasonal allergic rhinitis: a randomized study. Int Arch Allergy Immunol 2010; 151(2): 137-41.
- Brehmer D. Endonasal phototherapy with Rhinolight® for the treatment of allergic rhinitis. Expert Review of Medical Devices 2010; 7(1): 21-6.
- NHS Specialist Pharmacy Service Which medicines can be used to treat allergic rhinitis during pregnancy? Last updated July 2020. Accessed via: https://www.sps.nhs.uk/articles/which-medicines-can-be-used-to-treat-intermittent-allergic-rhinitis-during-pregnancy/. Last Accessed on: May 20, 2021.
- Golembesky A, Cooney M, Boev R, Schlit AF, Bentz JWG. Safety of cetirizine in pregnancy. J Obstet Gynaecol 2018; 38(7): 940-5.
- Shaikh WA, Shaikh SW. A prospective study on the safety of sublingual immunotherapy in pregnancy. Allergy 2012; 67(6): 741-3.