From the Guidelines
The most likely cause of your great toe nail turning white, also known as onycholysis or leukonychia, is a fungal infection, specifically onychomycosis, which can be diagnosed and treated by a healthcare provider. According to the British Association of Dermatologists' guidelines for the management of onychomycosis 2014 1, the clinical signs of tinea unguium are often difficult to distinguish from those of other infectious causes of nail damage.
Some key points to consider in the diagnosis of onycholysis or leukonychia include:
- The nail surface does not usually become soft and friable as in a fungal infection, but rather may exhibit other characteristics such as thinning of the nail plate, subungual hyperkeratosis, or dorsal pterygiium 1
- Nonfungal causes of nail dystrophies, such as chronic trauma, psoriasis, onychogryphosis, subungual malignant melanoma, and lichen planus, can also produce nail changes that mimic onychomycosis 1
- Repetitive trauma to the nail plate can result in distal onycholysis, leading to colonization of the affected space by infectious pathogens and discoloration of the nail plate 1
It is essential to consult a healthcare provider for proper diagnosis and treatment, as they can determine the underlying cause of the white discoloration and recommend the most effective course of treatment. In the meantime, keeping your feet clean and dry, wearing breathable shoes, and avoiding sharing nail tools can help prevent further complications.
From the Research
Causes of White Nail Syndrome (Leukonychia)
- Fungal infections, primarily caused by dermatophytes, such as Trichophyton rubrum, can lead to onychomycosis, which may cause the nail to turn white 2.
- Yeasts, including Candida parapsilosis and Candida guilliermondii, can also cause fungal nail infections, leading to white nail syndrome 2.
- Molds, such as Fusarium species and Onychocola canadensis, can cause non-dermatophyte onychomycosis, which may result in white nails 2.
- Bacterial infections, including those caused by Pseudomonas aeruginosa, Klebsiella spp., and Staphylococcus aureus, can also cause nail infections, potentially leading to white nail syndrome 2.
- Trauma to the nail, including repeated minor trauma, can make the nail susceptible to fungal infection, leading to onychomycosis and potentially white nail syndrome 3, 4.
- Foot and toe deformations, such as hallux valgus and hallux valgus interphalangeus, can increase the risk of developing onychomycosis, which may cause white nail syndrome 3.
- Immune system deficiencies, including those caused by autoimmune diseases, can increase the risk of developing onychomycosis, which may lead to white nail syndrome 5.
- Other factors, such as poor peripheral circulation, diabetes mellitus, and increasing age, can also contribute to the development of onychomycosis and white nail syndrome 4, 5.
Types of Onychomycosis
- Distal lateral subungual onychomycosis: starts at the hyponychium and spreads proximally to the nail bed and matrix 4.
- Proximal subungual onychomycosis: the fungus infects the cuticle and eponychium to reach the matrix where it becomes enclosed into the nail plate substance 4.
- Total dystrophic onychomycosis: may result from either form or develop in chronic mucocutaneous candidosis 4.
- Superficial white onychomycosis: commonly a culture of T mentagrophytes on the surface of a toenail 4.
- Mycotic paronychia and onycholysis: usually due to C albicans 4.
Treatment of Onychomycosis
- Topical antifungal agents, such as amorolfine and ciclopirox, can be used to treat onychomycosis 2.
- Oral antifungal agents, such as terbinafine, fluconazole, and itraconazole, can be used to treat more severe cases of onychomycosis 2, 6.
- Treatment of underlying conditions, such as foot and toe deformations, can help prevent the development of onychomycosis and white nail syndrome 3.