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All About Allergies: Be Ready for Spring

Praveen Buddiga, MD | March 22, 2019 | Contributor Information

Spring allergies are triggered as trees start blooming and billions of pollen grains are released into the air, causing susceptible individuals to develop allergic rhinitis (hay fever).[1-6] In these patients, the pollen causes degranulation of mast cells, which contain inflammatory mediators (histamine and other allergy-causing chemicals). This process is clinically represented by the following:

  • Sneezing
  • Red, tearing eyes
  • Postnasal drip
  • Sinus headaches
  • Feelings of sinus fullness
  • Itchy, scratchy throat

In addition to these symptoms, inflammatory mediators lead to swelling and hypertrophy of the nasal turbinates, as well as to possible loss of taste and smell.[7,8] In 2017, 19.9 million adults in the United States were diagnosed with hay fever over a 12-month period.[9]

Pollen can also trigger asthma attacks, with inflammatory mediators from degranulated mast cells causing airway inflammation, bronchial hyperresponsiveness, and airflow obstruction—this last being a consequence of factors such as acute bronchoconstriction, airway edema, and mucous plug formation.[10]

The child in the image has so-called allergic shiners, a term describing the periorbital edema that can occur in allergic rhinitis and sinusitis.

Image courtesy of Wikimedia Commons / katsrcool.

All About Allergies: Be Ready for Spring

Praveen Buddiga, MD | March 22, 2019 | Contributor Information

Tree pollen typically is the primary culprit in spring allergies, being airborne between the start of February and mid-June in some parts of the United States.[11] However, the timing of pollen spread varies geographically, depending on a region's weather, winter climate, drought patterns, and tree species. In the Central California olive tree, for example, pollen usually is highly active in late March and early April. The infamous cedar fever (caused by the Ashe juniper [Juniperus ashei], shown in the slide) occurs in Central Texas during the months of December and January, though in some cases it may encroach into March.

Image courtesy of Dreamstime / Vbaleha.

All About Allergies: Be Ready for Spring

Praveen Buddiga, MD | March 22, 2019 | Contributor Information

Pollen initiates an allergic reaction only in persons with allergic antibodies (immunoglobulin E [IgE]) that recognize it. Mast cells in the nasal and respiratory passages, sinuses, throat, and eyes are sensitized with IgE, ultimately releasing histamine and other inflammatory mediators, which cause sneezing, coughing, wheezing, and tearing of the eyes.[7,8] The use of nonsedating antihistamines, nasal corticosteroids, inhalant corticosteroids, and eye drops with antihistamines and mast-cell stabilizers may help mitigate these symptoms.[12]

Family history plays a significant role in an individual's predisposition to allergies. If one parent has allergies, then it is likely that at least one of multiple children will also have them; the likelihood is greater if allergies affect both parents.

Image courtesy of Wikimedia Commons / Doc. RNDr. Josef Reischig, CSc.

All About Allergies: Be Ready for Spring

Praveen Buddiga, MD | March 22, 2019 | Contributor Information

The predominant types of allergens vary according to the season, though there may be some carryover from one season to the next. Global warming and climate change are also now affecting which allergens occur at specific times of the year. Moreover, rising temperatures lengthen the period for pollen release, with greater pollen exposure expected to cause more allergy cases and with pollen counts possibly more than doubling from their 2012 values by 2040.[13,14]

As mentioned, trees pollinate from late winter to late spring; thus, tree pollen is the predominant cause of early spring allergies. Spring pollinators include the following[15-17]:

  • Birch
  • Beech
  • Ash
  • Cedar
  • Olive
  • Juniper
  • Sycamore
  • Red alder
  • Oak
  • Pine (pollen grains are shown in the slide)
  • Poplar
  • Cottonwood
  • Hickory
  • Box elder
  • Maple
Image courtesy of Wikimedia Commons / H Zell.

All About Allergies: Be Ready for Spring

Praveen Buddiga, MD | March 22, 2019 | Contributor Information

Grasses pollinate during late spring and summer. The major grass types throughout the United States include the following[16-18]:

  • Bermuda
  • Rye
  • Orchard
  • Fescue
  • Kentucky bluegrass
  • Redtop
  • Sweet vernal
  • Timothy (shown)
Images courtesy of Wikimedia Commons / Matt Lavin (top left), Nigel Cattlin / Science Source (top middle), Gilbert S Grant / Science Source (right), Wikimedia Commons / Geoff Gallice (bottom left), and Dennis Kunkel Microscopy / Science Source (bottom middle).

All About Allergies: Be Ready for Spring

Praveen Buddiga, MD | March 22, 2019 | Contributor Information

Weeds pollinate during late summer and fall. The most prominent weed in the United States, making up about 75% of the weed burden, is ragweed (Ambrosia artemisiifolia). One ragweed plant is able to produce up to 1 billion pollen grains. Other weeds that cause allergy symptoms by releasing pollen into the air include the following[16]:

  • Lamb's quarters
  • Pigweed
  • Russian thistle
  • Sagebrush
  • Cocklebur
  • Plantain
  • Mugwort
Image courtesy of Wikimedia Commons / Jon Houseman and Matthew Ford.

All About Allergies: Be Ready for Spring

Praveen Buddiga, MD | March 22, 2019 | Contributor Information

Most molds, whose habitats include rotting logs and fallen leaves, do not follow a clear seasonal pattern for allergen dispersal. They are primarily dependent on weather patterns to release their spores, with some needing dry, breezy weather and others requiring high humidity and the resulting fog or dew. The major types of allergy-causing molds include the following[19]:

  • Alternaria
  • Cladosporium
  • Penicillium
  • Aspergillus
  • Epicoccum
  • Fusarium
  • Mucor
  • Rhizopus (sporangia, the mold's spore-bearing structures, are shown in the slide)
Images courtesy of Wikimedia Commons / Herakrieger.

All About Allergies: Be Ready for Spring

Praveen Buddiga, MD | March 22, 2019 | Contributor Information

Allergic conjunctivitis (shown) is characterized by irritation and redness of the eyes and is common in allergy season. Like the nasal mucosa, the conjunctiva of the eye is a mucosal surface; consequently, pollen and other allergens that trigger allergic rhinitis can also cause allergic conjunctivitis. Contact between an allergen (eg, pollen) and the eyes causes ocular mast cells to release inflammatory mediators, including histamine, a reaction that can be prevented by using eye drops containing antihistamines, mast-cell stabilizers, or both (dual-action eye drops). Antihistamines found in eye drops include ketotifen, azelastine, olopatadine, and epinastine; mast-cell stabilizers include pemirolast, lodoxamide, bepotastine, alcaftadine, and olopatadine.[20,21]

Image courtesy of Medscape.

All About Allergies: Be Ready for Spring

Praveen Buddiga, MD | March 22, 2019 | Contributor Information

A cold can often be differentiated from an allergy on the basis of the length and timing of symptoms. A cold, commonly caused by a rhinovirus, usually lasts 7-10 days. If symptoms continue beyond the 10-day mark and develop on a recurring basis, this may indicate the presence of an allergic condition. Allergy is also indicated if symptoms recur at the same time every year.

Despite similarities in presentation, asthma and bronchitis can be differentiated clinically. In asthma, chest radiography may show hyperinflated lungs, whereas physical examination reveals wheezing caused by airway narrowing that inhibits expiratory air flow. Symptoms also include cough and chest tightness or "congestion." The high-resolution computed tomography (CT) scan in the slide, obtained during expiration in a patient with asthma, reveals a mosaic pattern of lung attenuation. Lucent portions (arrows) demonstrate areas of air-trapping.

Bronchitis is an inflammation of the bronchial tubes. Mucus buildup interferes with the movement of air into and out of the lungs, and wheezing, coughing, and sputum production may occur. The cause of bronchitis can be bacterial or viral.

Image courtesy of Medscape.

All About Allergies: Be Ready for Spring

Praveen Buddiga, MD | March 22, 2019 | Contributor Information

Inadequate allergy treatment can result in complications. Allergic rhinitis, for example, can lead to the following[4,5]:

  • Chronic or acute sinusitis – This can result when the inflamed nasal turbinates block the natural drainage of the sinuses through the ostiomeatal complex
  • Otitis media – This is believed to occur when inflamed nasal passages interfere with the patency of the eustachian tube
  • Sleep disturbance
  • Chronic fatigue
  • Headache
  • Throat irritation

There is also evidence that allergic rhinitis, if not controlled, can worsen inflammation related to asthma.[22]

In the case of acute otitis media shown in the slide, a purulent effusion exists behind a bulging tympanic membrane.

Image courtesy of Wikimedia Commons / National Institutes of Health (NIH).

All About Allergies: Be Ready for Spring

Praveen Buddiga, MD | March 22, 2019 | Contributor Information

The slide demonstrates the skin-prick method of testing for antigens (eg, from trees, grass, weeds, dust mites, cat or dog dander, and mold). The test elicits a wheal-and-flare response if the patient is allergic to a specific allergen. Allergy results may also be derived by extracting blood and running a radioallergosorbent test (RAST) or an ImmunoCAP test for IgE, but it takes a few days to obtain results from these studies.

Images courtesy of Wikimedia Commons: Mysid (top left), Harbin (top right), Fuse809 (bottom).

All About Allergies: Be Ready for Spring

Praveen Buddiga, MD | March 22, 2019 | Contributor Information

Decisions by the US Food and Drug Administration (FDA) to permit over-the-counter (OTC) use of second-generation antihistamines (commonly referred to as nonsedating antihistamines, though sedation may occur in some patients) and nasal corticosteroids have increased the OTC options for allergy symptom control. Available OTC second-generation antihistamines include the following[12]:

  • Fexofenadine
  • Loratadine
  • Cetirizine

OTC nasal corticosteroids include fluticasone and triamcinolone.

Images courtesy of Wikimedia Commons: Jynto (left), NEUROtiker (right).

All About Allergies: Be Ready for Spring

Praveen Buddiga, MD | March 22, 2019 | Contributor Information

Allergy symptoms can also be managed with nasal decongestants. Patients should be warned, however, that nasal decongestant sprays (ie, topical vasoconstrictive medications), such as those containing oxymetazoline, can cause inflammation, rhinitis medicamentosa, and bleeding.[23]

The decongestant pseudoephedrine can be taken orally but has a tendency to increase blood pressure; it should therefore be used with care if high blood pressure is a problem.

Nasal sinus irrigation with physiologic saline, placed in a plastic syringe or plastic rinse bottle, can also aid sinus drainage.

Image courtesy of Medscape.

All About Allergies: Be Ready for Spring

Praveen Buddiga, MD | March 22, 2019 | Contributor Information

Allergy immunotherapy—that is, the use of allergy shots—can reduce sensitivity to allergens.[24-27] Initially, patients receive a gradually increasing injected dose of allergens, which builds up to a maintenance dose. It is hypothesized that the injected allergens elicit a protective immune response in the patient by increasing his or her levels of IgG4 and regulatory T cells (Tregs). This allows the individual's immune system to respond to an allergen in the environment rapidly and aggressively enough to prevent the activation of an allergic cascade of events. A course of allergy shots takes 3-5 years.

The most important possible side effect that can arise from this therapy is an anaphylactic event. Consequently, after receiving an allergy shot, patients are required to remain under observation in their doctor's office for 30 minutes.

A newer treatment, sublingual immunotherapy (SLIT), in which the allergen is placed in tablet form under the tongue, is believed to be nearly as effective as allergy shot therapy. In 2014, the first SLIT drug, Oralair, received US Food and Drug Administration (FDA) approval for use against multiple grass pollens (sweet vernal, orchard, timothy, Kentucky bluegrass, and perennial rye).[28] Additional SLIT products have since been approved.[12,29]

Image courtesy of Medscape.

All About Allergies: Be Ready for Spring

Praveen Buddiga, MD | March 22, 2019 | Contributor Information

Allergy prevention measures include the following:

  • Limiting exposure to pollen and other allergens by remaining indoors on days when the pollen count is high or air quality is poor
  • Keeping windows closed during the morning; pollen counts tend to be high at this time of day
  • When driving, putting the car's ventilation in recirculation mode or using the air conditioner, which can limit the amount of pollen inside the car

A swollen, boggy nasal turbinate, a common finding in allergic rhinitis, is shown in the slide.[6]

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