Only 50% of dystrophic nails are due to fungal infection.

1. Examine the patient all over – do they have psoriasis?

2. The association of pitting and onycholysis is diagnostic of psoriasis.

3. Is there paronychial inflammation? If so, the nails are probably being damaged secondarily (check footwear when toenails affected).

4. Is there vesicular or scaly eczema on the fingers or toes? Eczema may damage the nails secondarily.

5. An isolated onycholysis of one big toenail may represent an underlying bony spur (exostosis). X-ray might demonstrate this (check footwear first).

6. Remember that tinea or yeasts can secondarily affect nails, particularly if damaged by a dermatosis (eg: eczema or psoriasis).

7. All patients with nail dystrophy should have nail clippings (and this should include scraping of loose material from under the nail if present). These samples should be sent for mycology (direct KOH examination and culture). The larger the specimen collected the better.

8. Oral antifungal treatment should only be prescribed after a positive culture or microscopy. Specimen collection should be repeated after negative mycological results if fungal infection is still strongly suspected.

Treatment will be discussed under fungal infection.

We suggest that you train your Practice Nurse to take clippings and show how to scrape under the nail.