Dictionary of Allergies .. Adenoids

The adenoids are a large mass of lymphoid tissue located on the posterior wall of the nasopharynx. They first appear during embryogenesis and continue to enlarge in response to antigenic stimulation from shortly after birth through puberty when they generally regress. Between 4 to 10 years of the age they achieve their largest size in relation to their anatomic location. The clinical classification of disease in the adenoids can be infection (adenoiditis and recurrent acute adenoiditis, chronic adenoiditis). Obstruction of the airway or Eustachian tube and neoplasia (benign or malignant).

Chronic or recurrent infection and obstructive hyerplasia are the two commonest manifestations of disease of adenoids. A history of persistent rhinorrhea, postnasal drip and chronic cough is common but not specific for adenoid hyperplasia and may occur in chronic adenoiditis, allergic rhinitis and chronic sinusitis. Snoring which is almost always present in children with obstructive adenoid hyperplasia, is rarely seen in children with allergic rhinitis and chronic sinusitis. Adenoid hyperplasia alone can induce sleep apnoea syndrome. The child may have classical "adenoid facies"[1] with an open-mouthed, dull appearance; elongated face; and dark circles under the eyes.

Similar appearances are seen in children with other causes of chronic nasal obstruction such as allergic rhinitis (allergic shiners). Abnormalities in dentition and in the maxillary-mandibular relationship may be apparent. Allergy evaluations may be necessary particularly in children with other signs and symptoms of allergic disease.

Two major immunological functions have been proposed for adenoids and tonsils: 1) local immunity and 2) immune surveillance. It has been demonstrated local antibody production by tonsil and adenoid B cells in response to specific antigens. Increased numbers of immunocytes well as shifts in the relationships between T-helper and T-suppressor cells are associated with increased bacterial loads and the presence of H. influenzae. The presence of chronic or recurrent infection have been shown to result in both increased and decreased levels of serum immunoglobulins. Other immunologic function include the production of mediators of the immune response, the modulation of B-cell activity and by T-helper and T-suppressor cells, and population of antigenically primed lymphocytes to distant sites.

The question following adenoidectomy and tonsillectomy is still debated. After adenoidectomy, a decrease in local secretory IgA synthesis has been cited widely to defer doctors from recommending their removal. However, in light of further laboratory investigation and clinical observation the relevance of these findings is questionable. It has been demonstrated a decrease in the rate of throat infections after tonsillectomy. In the past had been promoted a possible relationship between adenoidectomy and tonsillectomy and the later development of Hodgkin lymphoma as a reflection of the removal of the "immune surveilance" function of the tonsils and adenoids. Review of the epidemiologic data has revealed no relationship between these phenomenon. (See tonsils)[2].

Atopy is associated with increased numbers of IgE+ and FcεRI+ cells in adenoids irrespective of whether the child has otitis media with effusion or adenoid hyperplasia [3]. Intracellular expression of CTLA4 and FasL in T lymphocyts of the adenoid tissue may be a predictive factor in the development of respiratory allergy in children. Further studies are needed [4].

References

1. Elluru RG. Adenoid facies and nasal airway obstruction: cause and effect? Arch Otolaryngol Head Neck Surg. 2005 Oct;131(10):918.  Comment on: Arch Otolaryngol Head Neck Surg. 2005 Oct;131(10):919-20.

2. Brodsky, L.: Modern Assessment of Tonsils and Adenoids. Ped. Clin. of N. Am. Vol. 36, No. 6, p. 1551-1569, Dec. 1989.

3. Papatziamos,G et al: Increased occurrence of IgE+ and FcεRI+  cells in adenoids from atopic children. Allergy 1999:54:916-925.

4. Zakrzewska A, Kobos J, Górski P. The implications of nasal associated lymphoid tissue in development of respiratory allergic diseases in children. Med Wieku Rozwoj. 2007 Apr-Jun;11(2 Pt 1):129-34.