All about allergies, p.5
All About Allergies, page 5
The sinuses produce nitric oxide, which has antimicrobial properties and helps improve oxygen uptake. You may have heard that humming may increase nitric oxide levels in the nasal cavity, which could help reduce symptoms of sinusitis and rhinitis. However, there is limited data on whether this works and the only case report that I found reported on one person who had to hum strongly at a low pitch for one hour at bedtime the first night and 60 to 120 times at roughly 18 hums per minute, four times a day for the following four days as treatment for severe chronic rhinosinusitis to see benefit. That is a lot of humming!
Throughout your nose and sinuses, there is mucus, which is often called snot. Mucus is a slippery, gelatinous fluid that covers mucus membranes, which are found not only in your nose and sinuses but also in other parts of your body, such as your mouth, throat, and gastrointestinal tract. Mucus acts like flypaper and traps foreign particles and pathogens. Hair cells covering the respiratory tract move the debris that is trapped in mucus toward your throat to clean the respiratory tract during a process called mucociliary clearance. An adult typically swallows approximately 1 to 1.5 liters of nasal mucus each day, an amount that can significantly increase during an illness! In addition, nasal mucus contains antimicrobial proteins such as lysozyme and lactoferrin to help fight off pathogens. Mucus also helps prevent tissues from drying out. Mucociliary clearance does not work as well under dry conditions.
Your sinuses also produce mucus to clear pathogens from your respiratory tract. The mucus exits the sinuses through openings called ostia. However, inflammation in the nasal cavity from conditions such as allergic rhinitis or an upper respiratory infection may obstruct the sinus ostia, which disrupts mucociliary clearance. In dry conditions, the hair cells may not work as well, so mucus may accumulate in the sinuses. Upper respiratory infections stimulate more nasal mucus production, which can fill up the sinuses. Excess mucus in the sinuses allows viruses and bacteria to grow, causing an infection known as sinusitis.
The color of your snot may provide clues as to what is going on with your nasal passages. Clear or white mucus is usually seen in people who are healthy or if you have allergic rhinitis. Yellow or green mucus often indicates an infection. These colors occur because neutrophils release enzymes that change the color of the mucus. However, these colors do not reliably distinguish whether the infection is due to a virus or bacteria, so it does not automatically mean you need antibiotics if your snot is green. Red mucus usually means there is blood, which could be from an irritation in your nose, trauma, a foreign body, or potentially a mass in rare instances. Brown or black mucus could be due to a fungal infection or environmental pollutants. We will discuss this topic again in more detail in chapter 6 to frame it in the context of sinusitis.
The Throat
The throat is also known as the pharynx, which is a muscular tube that connects to the respiratory and gastrointestinal tracts. There are three areas of the pharynx. The nasopharynx is the uppermost region of the pharynx, which is above the soft palate in your mouth but near the back of your nose. This is where the Eustachian tube is located. The oropharynx is at the back of your mouth. When you swallow food, the soft palate elevates to close off the nasopharynx to prevent food from moving into your nasal cavity. The laryngopharynx is the lowest point of the throat, where food and air enter the esophagus and larynx, respectively. The epiglottis is the flap of cartilage that covers the larynx when you swallow, to prevent food from entering your lungs.
The tonsils are oval-shaped tissues in the oropharynx, and they are like lymph nodes because they help fight off infections. There are four sets of tonsils: palatine tonsils, pharyngeal tonsils, lingual tonsils, and tubal tonsils. The tonsils that you probably think of when looking at the back of your throat are the palatine tonsils. The pharyngeal tonsils are often referred to as the adenoid, which is in the back of your nasopharynx. When you open your mouth, the soft palate covers the adenoid, so it is not easily visible. Adenoid enlargement is common in children, and it can cause numerous symptoms, including mouth breathing, snoring, frequent ear infections, bad breath, nasal congestion, and sleep disturbances. If left untreated, children may develop a facial developmental abnormality called adenoid facies, which is a long face with an open mouth. Chronic or recurrent infections cause the immune system to be persistently activated, leading to enlargement of adenoid tissue. Allergies may cause chronic inflammation as well. Certain irritants such as tobacco smoke and pollutants can stimulate adenoid enlargement.
The Lungs
Your lungs help exchange oxygen from the air into your blood with carbon dioxide from your blood into the air. This occurs when air is moving into and out of the lungs (i.e., ventilation). Each lung has segments that are known as lobes. The right lung has three lobes while the left lung has two lobes. Think of your lungs as an upside-down tree where there are many branches. The respiratory tract is branched to increase its surface area to maximize gas exchange. When you breathe through your nose or mouth, air travels into the trachea, which is like the trunk of a tree. The two large branches that split off the trunk are called the left and right main bronchi. These bronchi further divide into smaller branches, called bronchioles, that are like twigs extending to the edges of the tree. The smallest unit of the lungs is the alveolus, which is where gas exchange occurs.
The diaphragm is a dome-shaped muscle that sits below the lungs and separates your chest cavity from your abdominal cavity; it is primarily responsible for ventilating air in and out of your lungs. When you breathe in, your diaphragm contracts and moves down, lowering the pressure inside your lungs. This allows air to flow into your lungs. Expiration is usually a passive process. However, if you are trying to blow air out of your lungs quickly, then your abdominal muscles and the intercostal muscles between your ribs also play a role. There are also smooth muscles surrounding the alveoli that are critical in opening your airways (i.e., bronchodilation) by relaxing when their beta-2 receptors become activated. The commonly prescribed rescue inhaler contains albuterol, which activates beta-2 receptors to quickly cause bronchodilation.
If you are having trouble breathing (i.e., dyspnea), then additional muscles are recruited to help with ventilation. Examples include the sternocleidomastoid, upper trapezius, and scalene muscles. These muscles are in the neck, upper back, and sternum to help with inspiration. If a young child is in respiratory distress, you may notice that their head is bobbing when these muscles contract. The opening of their nose may spread wide open (i.e., nasal flaring), and you may hear grunting to help keep their lungs open. Any of these signs in children requires immediate medical attention.
The Gastrointestinal Tract
The immune system in the gastrointestinal tract maintains a delicate balance between defense against pathogens and toleration of food. It must tolerate the gut microbiome, which is the ecosystem of microorganisms that live in your gastrointestinal tract. The innate immune system is present throughout your gut because its lining acts as a physical barrier. Your stomach acid provides a first line of defense against many pathogens by directly destroying them. The adaptive immune system in the gastrointestinal tract contains gut-associated lymphoid tissue (GALT) where plasma cells produce immunoglobulin A (IgA) antibodies that help neutralize toxins and pathogens. There are regulatory T cells (Tregs) in the gut that promote tolerance of food and resident microorganisms.
Nausea and vomiting are essential defense mechanisms to help remove harmful substances such as toxins and pathogens. How does the immune system cause vomiting? There are multiple mechanisms, but mast cells are primarily involved by releasing chemicals such as histamine to trigger vomiting. This is why antihistamines such as dimenhydrinate (Dramamine), meclizine (Bonine), and promethazine (Phenergan) are used to treat nausea and vomiting.
Mast cells may also be responsible for causing diarrhea by releasing serotonin and histamine. These mediators stimulate fluid secretion into the gastrointestinal tract, contributing to diarrhea. T cell activation can also contribute to diarrhea by increasing intestinal permeability and stopping the function of certain ion channels that are responsible for sodium and water absorption, so fluid accumulates in the gastrointestinal tract.
The Skin
The largest organ in your body is saved for last in this chapter. Skin is composed of three primary layers: the epidermis, the dermis, and the hypodermis. The epidermis is the outermost layer of skin, which is composed of several sublayers. It provides a barrier against irritants, allergens, and pathogens and prevents water loss. Keratinocytes are cells in the epidermis that provide the physical barrier and produce cytokines and antimicrobial peptides that help start an immune response. Just beneath the epidermis is the dermis, which consists of hair follicles, nerves, blood vessels, and connective tissue. This layer provides structure to the skin, regulates body temperature, and provides nutrients to the skin. The hypodermis is also known as the subcutaneous layer, which contains mostly connective tissue and fat. This layer helps provide energy, insulation, and a shield against physical forces.
A type of dendritic cells in the epidermis called Langerhans cells plays a crucial role in initiating allergic reactions in the skin. These cells capture antigens and travel to local lymph nodes to activate T cells, which starts the adaptive immune response. T cells also found in the skin are known as resident memory T cells because they respond quickly to previously encountered pathogens. B cells and plasma cells are present in the skin to produce antibodies that neutralize pathogens. The immune system in your skin also interacts with nerve cells and the bacteria on your skin that may alter the immune responses.
A rash may be a sign of an underlying process driven by your immune system. Rashes are mainly divided into primary and secondary skin lesions. Primary skin lesions are changes to the skin due to an internal problem; they include macules, patches, papules, plaques, pustules, nodules, vesicles, and bullae. Macules are flat lesions that are usually less than 1 cm in diameter, while patches are larger. Papules are small, raised lesions less than 1 cm in diameter, while plaques are larger. Pustules contain pus, which is a thick, opaque fluid that contains dead white blood cells and pathogens. Nodules are larger and deeper than papules and may go into the subcutaneous layer. Vesicles are small, fluid-filled lesions that are less than 1 cm in diameter, while bullae are larger.
Secondary skin lesions are changes that occur in primary skin lesions due to external factors such as scratching or the natural progression of a disease. Examples include crusts, scales, erosions, ulcers, fissures, atrophy, and lichenification. Crusts are dried blood or pus on the surface of the skin; they are often seen after vesicles or pustules have ruptured. Scales are flakes of dead epidermal cells, which are usually due to accumulation of keratin or abnormal skin shedding. Erosions are shallow losses of epidermis that heal without scarring. These are often seen after a vesicle or bullae rupture. Ulcers are deeper losses of skin than erosions but may still heal without scarring. Fissures are cracks in the skin that may extend into the dermis, which is often seen with eczema. Atrophy is thinning of the skin, while lichenification means the skin has thickened.
I know these last couple of chapters were not necessarily the most exciting, but you should now have the foundational knowledge needed to take on the rest of this book. We can now move on to the practical clinical aspects!
Take-Home Points
Lymph nodes are strategically placed throughout your body to quickly respond to infections.
The mucus that covers many of your organs helps lubricate and protect your body from pathogens.
Your sinuses may become clogged because there is excess mucus production, impaired mucociliary clearance, and/or increased inflammation of the surrounding tissues.
Chapter 4
What to Expect at the Allergist’s Office
Jessica was an elementary school teacher who loved her students. It brought her so much joy to see her students learning. She knew she was making a difference in their lives. Jessica also had two boys at home who kept her on her toes. Despite having her hands full, she was able to run a couple of marathons each year. Jessica had some mild allergies that did not bother her unless she was around cats. As a child, she used to wheeze and her doctors labeled her with asthma, but at this point in her life, she rarely used her albuterol inhaler unless it was prior to a long run. Jessica felt that she was healthy.
On one September day, she woke up with a fever, chills, cough, stuffy nose, and muscle aches. She was not overly concerned about it because she felt that it was a part of the job—kids pass germs all the time. However, she swabbed her nose at home and tested positive for COVID-19. She had to take off work for the rest of the week to recover and not pass the infection to her students.
At first, the symptoms felt like the flu and her fever broke after two days. She went back to work, but she felt more tired than usual for a couple of weeks. Jessica noticed that her cough never went away completely. She started using her rescue inhaler again, which helped control the cough, but she relied on the inhaler multiple times each day to get through her classes. Jessica also had a hard time breathing through her nose. She tried various cough, cold, and allergy medications that she could find at the pharmacy, but nothing seemed to give her complete relief.
After four weeks of dealing with these symptoms, Jessica had had enough. She called her doctor, who was able to squeeze her in for an office visit the next day. When she saw her doctor, they told her that she would benefit from allergy testing, so they referred her to an allergist, who happened to be me.
Navigating the healthcare system can be quite confusing, challenging, and sometimes scary. This chapter will help prepare you for a visit with an allergist. Many of the concepts covered in this chapter will also apply to navigating healthcare in general, so I believe anyone will find this chapter to be helpful.
Preparations for a Visit with an Allergist
If you need to see an allergist—or any specialist, for that manner—then you need to be prepared for the office visit. One of the most important aspects of the office visit is to be able to effectively communicate your concerns. The acronym RELIEF can be used to remember the key details for an effective office visit:
Record symptoms
Educate yourself
List medications
Identify concerns
Explain reactions
Follow advice
Record your symptoms ahead of the office visit. Create a symptom diary and keep track of the symptoms you have been experiencing. There are several questions that may help your doctor figure out what is going on. Where is the location of the symptoms? How intense are these symptoms? When did the symptoms start? How frequent are these symptoms? How long do the symptoms last? Are there any patterns to when the symptoms start? Do the symptoms move anywhere on your body? Have you tried anything to make the symptoms better? What potentially makes the symptoms worse? Have any other doctors examined you previously? If there are any rashes, please take pictures of them multiple times to show how the rash changes over time. I know it can be difficult to take pictures while problems arise, but it can make a doctor’s job a lot easier.
Spend time educating yourself on what you suspect may be going on. However, do not use Google indiscriminately, because many sources are not fully vetted, or they may cause more confusion or anxiety while you’re reading about various conditions. Instead, search for information from reputable organizations. Examples include the American College of Allergy, Asthma & Immunology (ACAAI), American Academy of Allergy, Asthma & Immunology (AAAAI), Asthma and Allergy Foundation of America (AAFA), Food Allergy & Anaphylaxis Connection Team (FAACT), and the American Lung Association.
When you come to the clinic, bring a list of all current medications and supplements that you are taking. List the previous treatments you have tried as well. If you saw previous doctors, then it will be very helpful to request a transfer of medical records as early as possible. Doctors in your area may not share the same electronic medical records system, so data may need to be faxed. I work at a small private practice, and I have access to one of the local community hospitals’ electronic medical records, but there are several clinics and hospitals that I do not have any access to. If the records arrive ahead of the office visit, there is a chance that your doctor may have an opportunity to review the records ahead of time, which will make the office visit more impactful. If your allergist wants you to fill out any forms, try to do this as early as possible so that time is not wasted on filling out paperwork while you are there. Do not be surprised if your allergist repeats questions that were asked on these forms. They may be trying to verify what you stated or clarify details that they want to learn more about.
Identify any concerns you have when you come for the office visit. What do you want to accomplish when you see the allergist? Are you looking for a diagnosis? A new treatment plan? When you are preparing to communicate your concerns, please do not hold back any information. Be as descriptive as possible. Explain previous reactions in as much detail as possible. The symptom diary can help jog your memory. I strongly recommend that you bring someone with you who can help advocate for you. It is easy to forget important details, and having another person with you who knows you well can help fill any memory gaps that may be crucial.
