Onychoscopy enters the dermatology diagnostic portfolio in India
January 14 2019
Similar to dermoscopy, onychoscopy allows detailed assessment of a nail and associated structures. Different onychoscopic patterns support naked eye examination and may help in avoiding nail biopsy. In 234 confirmed cases of onychomycosis, Kayathi Chetana and colleagues from Pondicherry in India found 5 common dermoscopic patterns: spikes (43%), jagged (30%), longitudinal striae (49%), linear edge (3%), and distal irregular termination (35%). Features of distal and lateral subungual onychomycosis (DLSO) were longitudinal striae, spikes, and jagged patterns. They also described 2 new patterns of bluish streaks and globules (9%) and bluish gray globules (8%) in some cases of DLSO.
The authors undertook an observational, prospective, cross-sectional study in 500 people with abnormal nails and/or nail folds. Onychomycosis was confirmed using a combination of potassium hydroxide microscopy, fungal culture and/or nail biopsy. Onychoscopy was done with a handheld 209 polarized contact dermoscope (Heine’s delta 20 T).
These findings in onychomycosis contrast with dilated and tortuous capillaries in nail psoriasis, longitudinal streaks and nail fragmentation in lichen planus, and enlarged capillaries in connective tissue diseases, as described by Yasmeen Bhat and colleagues from Srinagar, India. Other findings are summarized in a review by Lencrestre.
Yasmeen J. Bhat, Muzafar A. Mir, Abid Keen, Iffat Hassan. Onychoscopy: an observational study in 237 patients from the Kashmir Valley of North India. Dermatol Pract Concept 2018;8(4):6
Kayathi Chetana, MBBS, Roshni Menon, MD, DVD, and Brinda G. David, MD. Onychoscopic evaluation of onychomycosis in a tertiary care teaching hospital: a cross-sectional study from South India. International Journal of Dermatology 2018, 57, 837–842.
André Lencastre, MD, Ana Lamas, MD, Daniel Sá, MD, Antonella Tosti, MD. Onychoscopy. Clinics in Dermatology (2013) 31, 587–593.
Images from Bhat et.al. 2018