Allergic disease is one of the three most common reasons why patients visit their family physician. Respiratory diseases represent about 25% of all visits to general practitioners and about 80% of patients with recurrent presentations are found to be allergic. Allergy is a Greek word (allos = other and ergos = reaction) and allergen is a protein. Allergy is basically a childhood illness. Allergy can affect virtually any organ system. Common types of presentation include conjunctivitis (eyes), rhinitis (nose), urticaria and angioedema or atopic (allergic) dermatitis (skin), asthma (lungs), and anaphylaxis (multiorgan). Allergies are becoming more complex. Most of the patients with allergic diseases have involvement of multiple organs, i.e. multiple allergic diseases in the same patient. Children with allergies will do badly at school. Allergy affects their quality of life and physical activity.
Evaluation of suspected allergy must include a detailed medical history, comprehensive physical examination, and appropriate diagnostic tests. Diagnostic tests are detailed in Chapter 3.
The most important component of the evaluation of a possible allergic problem is the patient's history. Age at which certain allergic disorders commonly manifest is given in Table 1. A carefully taken history is the basis for the diagnosis and management of allergic diseases. Key features of history are mentioned in Box 1. The principle of history taking is the same as for any medical problem (When, Where, and What). Every allergy clinic must have a questionnaire to be filled up by the patient and the physician. History is far more important in the diagnosis and treatment plan of an allergic disorder. Without a thorough history, one cannot investigate the patient appropriately. Model allergy proforma is given in Appendix 1A, page 8.
Patient/parents must be given ample time to explain the symptoms. Many state that they have “sinus” or “permanent cold” or “this cold is not leaving.” They describe a wide array of symptoms ranging from itchy nose, eyes, or palate to runny nose or ear blocking or postnasal drainage to nasal congestion.
Sinus pressure and headaches are frequently cited as symptoms. “Popping or fullness of the ears,” implying Eustachian tube dysfunction, is an often-heard complaint. Asthma symptoms may be overt and present as wheezing, but descriptions may be more subtle, such as cough, tightness in the chest, or inability to get a good breath or let all the air out of the lung.
What seems to trigger symptoms? Cross-reaction with food substances should be enquired. For example, latex cross-reacts with banana and tree pollen with fruits. Food allergies are unusual if nonatopic. Patients often blame food for chronic urticaria.
History should help delineating the asthma as mild, moderate, or severe. Questions to determine the extent of asthma control include type and amount of inflammatory medication used (type of delivery system and quality of inhaler technique), frequency of respiratory symptoms and need for β-agonists, interference with daily activities or sleep, and diurnal peak flow variability if known. The degree of severity will ultimately the choice and intensity of treatment.
History of recurrent use of antibiotics, frequent attacks of cold, or cough in a supine position may point to chronic sinusitis. Gastroesophageal reflux can present solely as cough and sometimes mimic or exacerbate asthma. History should elicit the association of the symptoms with the same trigger during every attack.
We have to enquire from the patient/parent about the environment in which they are living. In most cases patient/parents will tell that their symptoms are worsening either indoor or outdoor.
These are recognized as important triggers and sensitizers of the allergic patient. The following questions are to be included in the history. Is the patient staying in damp/humid climate? What cleaning methods are used in the house? Whether dust mite bed/pillow covers are being used? Whether cockroaches are present in the house? Is the patient exposed to irritants? For example, incense stick smoke, mosquito coil, strong odors, perfumes, and detergents. Has the house been painted recently?
- Type of cooking fuel used in the house, especially biomass fuel
- Is there any exposure to the tobacco smoke at home?
- Is the house ill ventilated?
- Is there any leak of water in the house or in the bathrooms? (wet walls predispose to fungus.)
History taking should include the following questions regarding outdoor triggers. For example, exposure to automobile pollution, exposure to pollens from trees, grasses and weeds in the locality, presence of lawns/factory/fire works or on going constructions nearer the place of stay.
Particular attention should be given to any exposure to pets. Do the pets sleep in the bedroom or on the bed?
Whether the patient is taking any antibiotics, nonsteroidal anti-inflammatory drugs (NSAIDs), opiates, or angiotensin converting enzyme (ACE) inhibitors should be enquired. What is the current medication that the patient is taking? Enquire about the usage of any over-the-counter medications or herbal/complementary products. Has the patient taken any anesthetic medications recently? Has the patient undergone any operation recently? What medications is the patient taking for the allergic disease currently, especially inhalation therapy for asthma or nasal allergy? Frequent use of decongestant nasal spray can lead to rebound nasal congestion, also called rhinitis medicamentosa. Is there any recent H/O radio-contrast dye ingestion? What drugs are being taken for nasal symptoms? How often relievers are used per month for asthma symptoms? Whether patient is using controller medications? How often is he taking antihistamines for nasal symptoms?
Past Medical History
Past history of atopic symptoms and prior autoimmune disease, especially thyroid disorders and regular β blocker usage, are to be enquired. Previous history of surgery is to be enquired for latex allergy. Is there any H/O dry skin during infancy (atopic dermatitis)? (Table 3) Is there any H/O otitis media with effusion/sinusitis/adenoid hypertrophy?
The family history of an allergic disease such as asthma and food allergies should be sought. Heredity is the most important determinant of the early onset of persistent asthma. The risk of atopy is increased from 25% in the general population to about 75% when both parents are atopic. In one study, 90% of allergic asthmatic children had one or both parents who were atopic. Maternal asthma is a risk factor for the offspring.
Enquire about using carpets/wall hangings or staying in dusty environment and ventilation of the house. The type of home and the presence of a basement may be important. For example, a wet environment tends to produce growth of molds and a humid environment, dust mites. House dust mite is the most common allergen in our society. Therefore, the kind of bedding, type of furniture, and type of flooring may be relevant to understand in a given patient. Daycare facilities can be an insidious source of recurrent viral and bacterial exposure for children.
Is the patient exposed to passive smoking (second-hand smoking)? What type of cooking fuel is used in the house?
It is also important in older children and adolescents as child labor is common in our country. Enquire about his/her work and find out how it is relevant to his/her symptoms.
Pitfalls in History
- Absence of known contact with pet does not exclude sensitization to animals or symptoms on exposure. Several recent studies show a very high level of cat allergens in homes, at school, in offices, theaters, and even doctor's office without the actual presence of cats.
- Patients with perennial disease have most of their symptoms in the bedroom during the early morning although the causal agent is not necessarily in the bedroom.
- Patients who have strong aeroallergen sensitivity and chronic low-dose exposure to the allergen, e.g. house dust mite or cat, will not notice immediate symptoms at home, but will notice symptoms from irritants (due to a nonspecific nasal hyperactivity) such as smoke, cold air, and perfumes. The patients will then assume that these are the allergens, when they are merely secondary irritant triggers. Therefore, the case history is rarely informative with regard to house dust mite allergy. A carefully taken history should be followed by an appropriate physical examination.
The physical examination may be entirely normal at the time of examination, because allergy symptoms and signs are often evanescent. We have to examine the organs involved with allergy symptoms. Muller's grading of the severity of IgE-mediated allergic reaction is given in Table 4.
An allergic patient's history may direct the clinician's examination to a particular area or organ system. Each patient should be approached in a systematic way. Often, physical examination may be normal and lack of findings does not rule out allergy.
Vital signs are the starting point in any examination. Pulse rate and pulsus paradoxus greater than 10 mm Hg are two of the most sensitive indicators of severe airway obstruction.
With the global increase in the use of inhaled corticosteroids for the treatment of allergic respiratory disease, growth in children should be more closely monitored. Height and weight should be measured periodically.
Examination of the main target organs of allergic diseases such as upper airways, ears, pharynx, nose, eyes, chest, and skin should be done thoroughly.
Clues to allergy are often seen in the patient's face. Discoloration of the infraorbital skin or “allergic shiners” may imply nasal congestion and subsequent lymph stasis.
Extension of the mid-face in children is often seen with adenoid hypertrophy; an infraorbital crease or Dennie's line and a transverse crease along the lower half of the nose are frequent but not absolute indicators of the underlying allergy. Details are described in Chapter 12.
The eye examination is concerned principally with the state of the tarsal (lower lids) or palpebral (upper lids) and bulbar conjunctivae. Look for watery discharge, swollen conjunctiva, and scleral injection.
Tympanic membranes should be visualized. Tympanosclerosis implies previous recurrent otitis. If the light reflex is not well appreciated or history suggests Eustachian tube dysfunction, the tympanic membranes should be examined, while the patient performs a Valsalva maneuver to test the patency of the Eustachian tube.
The nose is best examined with a torch in children. Look for deviated septum, hypertrophied inferior turbinates, bluish or pale nasal mucosa, clear rhinorrhea, and polyps. Purulent discharge is suggestive of infection.
The size and character of the tonsils should be noted. Finally, estimation of the depth and width of the oropharynx may lead to suspicion of obstructive sleep apnea. For those patients taking inhaled corticosteroids, thrush on the tongue and soft palate should be excluded at each visit.
The neck must be palpated to search for adenopathy. Usage of accessory muscles, especially sternocleidomatoids should not be missed, because it is another sign of marked airway obstruction.
The skin is commonly affected by allergy, although skin findings are often falsely attributed to allergic disorders. Individuals with atopic dermatitis have dry skin. Look for lesions of urticaria, dermatographism. The lesions of angioedema are usually not as well demarcated as urticarial lesions.
Respiratory System Examination
The lower respiratory system examination is particularly relevant in the asthmatic patients. Configuration of the chest wall should be noted, in particular, pectus excavatum, kyphosis, lordosis, and scoliosis should be ruled out by inspection. Intercostal retractions may imply severe obstructive disease.
POINTS TO REMEMBER
- ABAI: American Board of Allergy and Immunology. Archived from the original on 2010-11-16. Retrieved 2007-08-05.
- Bruce LW. Approach to the allergic patient. In: Phil L, John AA (Eds). Allergic Diseases: Diagnosis and Treatment, 3rd edition. Totowa, New Jersey: Humana Press; 2007. pp. 15–25.
- Francis MR. History taking in allergic diseases. JAMA. 1936;106(12):976–9.
- Franzese CB. AAOA allergy primer: history and physical examination. International Forum of Allergy & Rhinology. 2014;4(S2):S28–S31.
- Gell PGH, Coombs RRA. Clinical Aspects of Immunology. London: Blackwell; 1963.
- Ishizaka K, Ishizaka T, Hornbrook MM. Physico-chemical properties of human reaginic antibody. IV. Presence of a unique immunoglobulin as a carrier of reaginic activity. J Immunol. 1966;97(1):75–85.
- Johannes R. Clinical manifestation and classification of allergic diseases. In: Allergies in Practice. Germany: Springer; 2005. pp. 1–7.
- Von Pirquet C. Allergie. Munch Med Wochenschr. 1906;53(5):1457.
- Sporik R, Henderson J, O'B Hourihane J. Clinical immunology review series: an approach to the patient with allergy in childhood. Clin Exp Immunol. 2009;155(3):378–86.