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Argyria of nasal mucosa secondary to occupational silver exposure

October 24, 2007 – 7:26 am

Objectives: The aim of this paper is to present a rare cause of nasal mucosa pigmentation from silver exposure and the management of the condition.

Materials and Methods: A case of argyria of the nasal mucosa secondary to silver exposure in the photographic processing industry is presented.

Results: The clinical, histological findings of the nasal mucosa are consistent with the patient’s occupational exposure to the silver compound.

Conclusion: Argyria is a rare cause of nasopharyngeal mucosa pigmentation. The condition is suspected from patients with a history of chronic silver exposure. Biopsy of the mucosa is required for the diagnosis. Argyria does not increase the risk of nasopharyngeal carcinoma. Although silver itself is relative non-toxic to human body, appropriate occupational safety measures arc required to prevent the exposure of other toxic chemical compounds that are bound to the silver.

Introduction

Argyria is a rare condition that is caused by the permanent deposition of silver in the skin and the mucosa membrane. This results in a life long slate-grey pigmentation of the tissues. The deposition of silver in the eyes is known as argyrosis.1,2 This report includes a case of argyria of the nasal mucosa as a result of the silver exposure from the photographic film industry with the details of the management.

The patient had worked in the photography industry for many years preparing photosensitive media. He had a past history of chronic sinusitis and had three previous sinus surgeries. The presenting complaint was of recurrent right frontal headaches. Examination of the nasal cavities resembled a bluish-black discoloration of the nasal septal mucosa, the head of the middle and the inferior turbinates. (Figure 1)

The biopsy of sinonasal mucosa showed an extensive deposits of minute brown-black granules in the collagen of the stroma with features of argyria. (Figure 2) The pigment resisted melanin bleach. Initially, Rhodanine stain for silver did not show the typical brown colour expected for silver. However, the stain was performed on paraffin sections as the specimen was fixed in formalin. When Rhodanine stain was performed on frozen sections at a later date, typical brown colouration of silver was seen in the specimen.

Discussion

Argyria of the nasal mucosa appeared as a bluish-black discoloration. The differential diagnosis of a localised pigmentation that may resemble a localised argyria include melanoma,3,4 bismuth deposition and other heavy metal staining for example mercury and gold.5 Both Addison’s disease and haemochromatosis can also cause a localised black pigmentation of nasal mucosa.5

In the reported case, the patient had been working in the industry of manufacturing of photographic film for many years. In the preparation of photosensitive materials, silver nitrate is poured into a solution with sodium halides in gelatine to precipitate silver halides.6 The exposure to silver from his work is consistent with the silver deposit that was found extensively in his nasal mucosa.

In general, the diagnosis of argyria is made by occupational history and by noting the discoloration that may occur on the skin, and mucus membrane or conjunctivae. Characteristically, the workmen’s face, hands, and arms develop a dark slate-grey colour, which is uniform in distribution and varies in depth depending on the degree of the exposure. The discoloration can also occur in nasal, bronchial mucosa, fingernails and toenails. Covered parts of the body are affected to a lesser degree by the discoloration.7 Procedures to confirm the silver exposure include skin, mucosa biopsy, slit lamp examination of eye and blood level measurement. Slit lamp examination appears to be the best method to measure body burden to silver.8 Blood silver levels appear to reflect recent exposure only.8 No specific treatment, such as the use of chelating agents, is available or indicated.7 There is no complete effective and safe treatment for the removal of silver from the skin or the nasal and oral-pharyngeal mucosa.6,9 The only treatment of the cosmetic disability of argyria that has shown any success was the local application of a 5% hydroquinone cream on skin over a period of one year to patients with the occupational argyria. This reduced the number of silver granules particularly in the upper dermis and around the eccrine sweat glands.

From the extensive human, animal, clinical, epidemiological studies and occupational exposure studies, excessive silver absorption does not appear to produce any conclusive and recognizable disturbance of health.2,7,8,10 It has been postulated that the toxic effects of silver is neutralised by binding with selenide as well as sulfide and then bind to a protein to form the electron dense granules.6,10,11 Interesting, Stammberger12 described the possible association between argyria and nasopharyngeal carcinoma. However this view has not been supported by the available literatures and experimental studies. There were also isolated reports of associating silver exposure and neuropathy13,14 or renal damage15. However, the exact pathogenesis of these diseases induced by the silver was unclear and other cofounders like chemical compounds that were bound with the metallic silver may have caused the problems rather than the silver itself. The possibility of renal damage was raised by Owens and colleagues study16 but when examining this paper carefully, it was probably the sulfadiazine component of the sulfadiazine silver that caused the nephrotic syndrome and not the silver itself.