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Changes in nail thickness: causes, symptoms, diagnosis, treatment
Medical expert of the article
Last reviewed: 07.07.2025
On the hands, the normal thickness of the nail plate is on average 0.5 mm, on the feet - 1 mm. A decrease or increase in these indicators should be diagnosed as thinning or thickening of the nail.
Thinning of the nail plates occurs with koilonychia, as well as with exfoliating nails (lamellar dystrophy, or onychoschisis). Distal and proximal lamellar dystrophy are distinguished depending on the localization of the process. Distal lamellar dystrophy begins with the free part of the nail plate and develops with frequent contact with water, detergents, obligatory chemical irritants, including cosmetics for nail plates. According to the mechanism of development, distal lamellar dystrophy is a consequence of severe dehydration and delipidization of the nail plate.
Structural changes in the nail matrix lead to proximal lamellar dystrophy. Changes in the nail lunula are possible when taking a number of medications (synthetic retinoids, etc.), proximal onychomycosis, progressive psoriasis, and other diseases.
Thickening of the nail may be associated with thickening of the nail plate itself (pachyonychia) and with subungual hyperkeratosis.
Pachyonychia, or true thickening of the nail plate, can be a sign of a number of dermatoses, it is diagnosed in psoriasis, erythroderma of various genesis, atopic dermatitis, allergic dermatitis, alopecia areata, congenital ectodermal dysplasia, Reiter's disease. In chronic lymphostasis, a combined thickening of all nail plates with their yellowish coloration is often encountered.
Subungual hyperkeratosis is most often detected in onychomycosis caused by filamentous fungi. The severity of subungual hyperkeratosis. It can vary: moderate hyperkeratosis (1-2 mm) and pronounced hyperkeratosis (more than 2 mm) are distinguished. In addition, this phenomenon occurs in lichen planus, eczema, mycosis fungoides, psoriasis.
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