Onychogrypose L60.2

Lovibond 1938; Schamroth 1976;

Usually strongly arched, thickened, often yellowish or yellow-brownish discolored, claw-like, hardened nail. This is caused by a growth disorder of the nail root.

Irritation of the toenails due to unsuitable footwear.

Due to extreme neglect of personal hygiene (Ko D et al. 2018).

Chronic, repetitive trauma (e.g. from playing football; often the big toe nail is affected).

Predisposing effects, advanced age, peripheral circulatory disorders, chronic venous insufficiency, malpositioning of the foot (hallux valgus).

In autosomal dominant onychogrypose all toenails and fingernails can be affected from birth. The"Fischer syndrome" is also characterized by a congenital onychogrypose.

In case of traumatic genesis also occurring in younger people.

Otherwise mainly in older people (neglected nail care), especially with underlying diseases such as psoriasis, syphilis, leprosy, ichthyosis, diphtheria, mycoses, frostbite.

Primarily the toenails are affected; here it occurs mainly on the big toenails; less frequently other or several toenails are affected.

The nail is abnormal, sometimes grotesquely misshapen, thickened, and discolored—yellowish or yellowish-brownish. The surface of the nail is characterized by transverse ridges or longitudinal grooves.

Frequently (especially in the case of the big toe nail), the nail deviates laterally from its original direction of growth. Occasionally, a reversal of the growth direction (from horizontal to vertical) results in a grotesque thickening of the nail (see fig.). On the other hand, extreme neglect of nail hygiene can lead to formations in which the nail curls up in a spiral shape, like a ram’s horn (Chang P et al. 2015).

A particularly pronounced morphological variant is described as the so-called “arrowtail crab” nail growth anomaly . In this condition, the nail plate is massively thickened, hardened, and deformed, and bulges distally over a shortened or altered nail bed. This is often accompanied by pronounced subungual hyperkeratosis, tenderness, and significant mechanical impairment.

It is not uncommon for a complicating fungal infection of the nail to develop (see Fig.).

Elimination of the cause (e.g. chronic repetitive pressure), grinding and smoothing of the nail surface with a rotating burr. The flattened nail can be additionally covered with an occlusive patch (e.g. Zalain nail patch), which is changed weekly.

If the findings are pronounced, extraction of the nail with sclerotherapy of the nail matrix should be considered.

Experience has shown that onychogrypotent modified toenails do not regress over a longer period of time, as the nail root is irreversibly damaged.

1. Chang P et al. (2015) Onychogryphosis: A Report of Ten Cases. Skinmed 13:355-359.

2. Loth Fabia M et al. (2026). Onychogryphosis as a nail-bed problem—a novel approach with the potential for complete restoration. Journal of the German Dermatological Society, Early View 1–3. DOI: 10.1111/ddg.70511x⁠.

3. Ko D et al. (2018) Onychogryphosis: Case Report and Review of the Literature.Skin Appendage Disord 4:326–330.