What causes brown broken nails?

From the Guidelines

Brown broken nails are typically caused by fungal infections, trauma, or nutritional deficiencies, with fungal infections being the most common cause, as stated in the British Association of Dermatologists' guidelines for the management of onychomycosis 2014 1. The most common cause of brown broken nails is fungal infections, specifically onychomycosis, which can result in thickened, discolored, and brittle nails that can break easily. Some key points to consider when evaluating the cause of brown broken nails include:

• Fungal infections, such as onychomycosis, can be caused by various factors, including occlusive footwear, repeated nail trauma, genetic predisposition, and concurrent diseases like diabetes or immunosuppression 1.
• Trauma to the nail plate, such as repetitive actions like typing or sports, can damage the nail matrix, leading to weakness and breakage.
• Nutritional deficiencies, particularly of biotin, iron, and protein, can compromise nail strength and integrity.
• Medical conditions, such as psoriasis and thyroid disorders, may also contribute to nail problems. Treatment depends on the underlying cause, with fungal infections requiring antifungal medications like terbinafine (250mg daily for 6-12 weeks) or topical solutions like ciclopirox, while trauma-related damage needs time to heal with protective measures, and nutritional deficiencies should be addressed through diet improvements or supplements 1. Maintaining good nail hygiene, keeping nails trimmed, avoiding harsh chemicals, and using moisturizers can help prevent further damage while the underlying issue is being treated. It's essential to differentiate between onychomycosis and other conditions that may mimic its symptoms, such as bacterial infections, psoriasis, or lichen planus, by examining the nail bed and looking for characteristic patterns of intact longitudinal epidermal ridges stretching to the lunula 1.

From the Research

Causes of Brown Broken Nails

• Brown broken nails can be caused by various factors, including fungal infections, bacterial infections, and melanonychia, which is a condition characterized by black or brown pigmentation of the nails 2, 3.
• Fungal infections, such as onychomycosis, can cause brown discoloration and brittleness of the nails, leading to breakage 4, 5.
• Melanonychia can be caused by aberrant melanin production in the nail bed, and can also be a sign of underlying conditions such as cancer or infection 2, 3.
• Other factors that can contribute to brown broken nails include trauma, aging, and certain medical conditions, such as diabetes or peripheral neuropathy 4.

Fungal Melanonychia

• Fungal melanonychia is a rare nail disorder caused by fungal infection, which can produce brown-to-black pigmentation of the nail unit 5.
• This condition can be difficult to diagnose and differentiate from other causes of melanonychia, including subungual melanoma 6.
• Dermoscopy can be a useful tool in diagnosing fungal melanonychia, with characteristic features including a distal diffuse pattern, distal linear pattern, and light brown to yellowish color 6.

Diagnosis and Treatment

• Diagnosis of brown broken nails typically involves a combination of clinical examination, dermoscopy, and laboratory tests, such as biopsy or fungal culture 2, 3, 6.
• Treatment of brown broken nails depends on the underlying cause, and may include antifungal medications, antibiotics, or other therapies aimed at addressing the underlying condition 2, 4.