Allergy and Benign Lesions of the Vocal Cord Mucosa

Abstract

Hoarseness is a result of the vocal cords not working properly and it can be detected by hearing. Basic and higher harmonic tones are associated with severe hoarseness, as well as noises replacing the harmonic noise. Hoarseness can also appear as a result of organic changes of the vocal cords (also caused by allergic mucosal changes) or functional disorders. The most common organic changes of the vocal cords are polyps, nodules and Reinke's oedema (1). Under a microscope they share many common characteristics of mucosal changes and indicate pathological changes in the superficial layer of the lamina propria, in the so-called Reinke’s space (2). The main changes include: fluid oedema, elevated interstitial and exudative proteins, dilated or hypertrophic vein walls. The aetiology of the benign changes is, however, slightly different although the changes in the lamina propria are quite similar. The most common cause is trauma (phonotrauma), exposure to unfavourable microclimate conditions, smoking, voice overuse or incorrect vocal technique, hormonal changes, and allergy (3). Reinke's oedema is a swelling of vocal cords that mostly occurs bilaterally. It is a chronic benign condition. On examination a transparent, sometimes a pink swelling is seen along the length and on the upper side of the vocal cord. As long as the swelling remains small, the vocal cords can vibrate normally. However, as the oedema grows and therefore changes the biomechanics of the larynx, the functional impairment of the phonation appears, vocal cords do not vibrate appropriately and the voice becomes low-pitched and hoarse. Histologically, the mucosa is covered by a layer of normal and hyperplastic epithelium. By enlargement of the swelling, it may become atrophic. Persisting etiologic factors can cause the epithelium to thicken or become hypetrophic. Simple hyperplasia is the most common form of the epithelial changes due to hypertrophy (1). A polyp is a mucosal thickness usually found at the front midpoint of the vocal cord. It is most commonly thought to be caused by vocal overuse or incorrect vocal technique. It is very similar to the Reinke's oedema, except that the polyp is localised. Of all the benign oedematous vocal cord lesions, nodules are the smallest and by aetiology similar to polyps. The oedema is modified as in Reinke's oedema or polyps.