Authors' reply

Manjunath M Shenoy¹ , S Teerthanath² , Vimal K Karnaker³ , BS Girisha² , Krishna Prasad³ , Jerome Pinto¹

¹ Department of Dermatology, K.S. Hegde Medical Academy, Mangalore, Karnataka, India
² Department of Pathology, K.S. Hegde Medical Academy, Mangalore, Karnataka, India
³ Department of Microbiology, K.S. Hegde Medical Academy, Mangalore, Karnataka, India

Correspondence Address:
Manjunath M Shenoy
Department of Skin and V.D., Justice K.S. Hegde Charitable Hospital, Deralakatte, Mangalore - 574 160 Karnataka
India

Sir,

We thank Singh and Lavanya for showing interest and responding to our article "Comparison of potassium hydroxide mount and mycological culture with histopathologic examination using periodic acid-Schiff staining of the nail clippings in the diagnosis of onychomycosis". ^[1] We agree with some of the views expressed, however others may need reconsideration.

It is true that mycological culture has a higher specificity, but it has lower sensitivity as compared to histopathology with periodic acid-Schiff staining (HP/PAS). ^[1],[2] HP/PAS is relatively quick, and a specificity of 72% cannot be overlooked. ^[3] In most cases, morphological aspect of the hyphae and/or spores can suggest the group to which pathogens belong. ^[3] In personal view of the authors, cost of HP/PAS is not so high considering all these informations obtained after doing this test, and when compared to the cost of onychomycosis therapy.

HP/PAS is not an alternate test to mycologic culture. It a simple and highly sensitive screening test and can be performed as a complementary to mycological culture and potassium hydroxide (KOH) mount to close the diagnostic gap. ^[1] PAS staining can be performed routinely as a standard of practice in the lab diagnosis of onychomycosis, however, histochemical staining using Gomori methenamine silver may have higher sensitivity. ^[4] All these factors suggest that HP/PAS staining of nail clips should be considered as a valuable test in the diagnosis of onychomycosis.

1.	Shenoy MM, Teerthanath S, Karnaker VK, Girisha BS, Krishna Prasad MS, Pinto J. Comparison of potassium hydroxide mount and mycological culture with histopathologic examination using periodic acid-Schiff staining of the nail clippings in the diagnosis of onychomycosis. Indian J Dermatol Venereol Leprol 2008;74:226-9. [Google Scholar]
2.	Weinberg JM, Koestenblatt EK, Tutrone WD, Tishler HR, Najarian L. Comparison of diagnostic methods in the evaluation of onychomycosis. J Am Acad Dermatol 2003;49:193-7. [Google Scholar]
3.	Gianni C, Morelli V, Cerri A, Greco C, Rossini P, Guiducci A, et al. Usefulness of histological examination for the diagnosis of onychomycosis. Dermatology 2001;202:283-8. [Google Scholar]
4.	D'Hue Z, Perkins SM, Billings SD. GMS is superior to PAS for diagnosis of onychomycosis. J Cutan Pathol 2008;35:745-7. [Google Scholar]