From the Guidelines
Longitudinal ridges on thumbnails are primarily caused by noninfectious conditions, including aging, nutritional deficiencies, and trauma to the nail matrix, rather than infectious causes like onychomycosis. When considering the etiology of longitudinal ridges on thumbnails, it is essential to distinguish between infectious and noninfectious causes. According to the British Association of Dermatologists' guidelines for the management of onychomycosis 1, noninfectious conditions such as chronic trauma, psoriasis, onycholysis, onychogryphosis, subungual malignant melanoma, and lichen planus can produce nail changes that mimic onychomycosis.
Key Causes of Longitudinal Ridges
- Noninfectious conditions, including aging and nutritional deficiencies
- Trauma to the nail matrix
- Medical conditions like psoriasis, lichen planus, and other dermatological disorders
- Dehydration of the nail plate The presence of intact longitudinal epidermal ridges stretching to the lunula, as mentioned in the guidelines 1, can help differentiate between nail trauma and onychomycosis, suggesting that trauma is a possible cause of longitudinal ridges.
Importance of Accurate Diagnosis
Accurate diagnosis is crucial to determine the underlying cause of longitudinal ridges on thumbnails, as it may indicate an underlying health condition requiring specific treatment. A thorough examination of the nail bed and surrounding area can help differentiate between infectious and noninfectious causes.
Treatment and Prevention
Maintaining proper nutrition, regular moisturizing of nails and cuticles, and gentle buffing with fine-grit buffers can help reduce the appearance of longitudinal ridges. However, if ridges appear suddenly or are accompanied by other nail changes, medical evaluation is recommended to rule out underlying health conditions.
From the Research
Causes of Longitudinal Ridges on the Thumbnail
- Longitudinal ridges on the thumbnail can be caused by various factors, including benign tumors, malignant neoplasms, and other conditions such as hemiplegia and postsurgical scar 2
- Certain systemic conditions like Darier disease, acantholytic dyskeratotic epidermal nevus, and lichen planus can also lead to longitudinal ridges on the nails 2, 3
- Idiopathic cases of longitudinal erythronychia, where no underlying condition is found, can also present with longitudinal ridges on the thumbnail 2
- Trachyonychia, a condition characterized by rough nails, can also cause excessive longitudinal ridging on the nails, including the thumbnail 4
- Hailey-Hailey disease, a rare genetic disorder, has been associated with white longitudinal bands and ridges on the fingernails, including the thumbnail 5
Associated Conditions
- Longitudinal ridges on the thumbnail can be associated with other nail changes such as fragility, onycholysis, splinter hemorrhage, splitting, subungual keratosis, thinning, and V-shaped nick 2
- Systemic conditions like lichen planus, Darier disease, and amyloidosis can also present with longitudinal ridges on the nails, including the thumbnail 2, 3
- Nail changes, including longitudinal ridges, can be a clue to an underlying systemic disease or infection, and examination of the nails is essential at every medical visit 6