10 Nail Changes That May Indicate an Underlying Health Issue

10. Thickened Nails - Fungal Infections and Circulation Problems

Nail thickening, or onychauxis, represents a common nail abnormality that can result from fungal infections, poor circulation, aging, or various underlying medical conditions affecting nail growth and structure. Onychomycosis, the most common cause of nail thickening, affects millions of people worldwide and typically begins as a small area of discoloration that gradually spreads, causing the nail to become thick, brittle, and often yellow or brown in color. Fungal nail infections are particularly common in older adults, diabetics, and immunocompromised individuals, as these populations have increased susceptibility to fungal overgrowth and decreased ability to fight infections. The thickening occurs as the fungal organisms invade the nail plate and nail bed, disrupting normal nail architecture and causing accumulation of keratin debris beneath the nail. Poor circulation, particularly common in peripheral vascular disease and diabetes, can also lead to nail thickening as reduced blood flow impairs normal nail matrix function and slows nail growth, allowing for accumulation of nail material. Psoriasis can cause significant nail thickening through chronic inflammation of the nail matrix and nail bed, often accompanied by other characteristic features such as pitting, oil spots, or onycholysis. Age-related nail thickening is common and typically affects toenails more than fingernails, resulting from cumulative effects of reduced circulation, slower cell turnover, and repeated minor trauma over decades. Other causes of nail thickening include trauma, certain medications, genetic conditions, and systemic diseases affecting keratin production, making comprehensive evaluation important for determining appropriate treatment approaches and addressing underlying contributing factors.