The following symptoms and complaints may indicate exogenous (external) nail formation disorders* :
- Nail bed hematoma – bruising under the nail, leading to black discoloration of the nails.
- Leukonychia striata or Mees stripes – white horizontal stripes.
- Leukonychia punctata – punctate white coloration.
- Leukonychia partialis – circumscribed white coloration.
- Leukonychia totalis – complete, homogeneous, white discoloration of the fingernails without further structural disturbances.
- Onychogrypose – claw nails
- Longitudinal grooves of the nails can occur after frequent injuries or blunt damage
- Brittle nails
The following symptoms and complaints may indicate endogenous (internal) nail formation disorders in underlying diseases:
- Eczema nails
- Green nail syndrome (synonyms: chloronychia; green nail; English green nail syndrome) – color of the nail can vary as follows: yellowish-green, green, green-purple or even green-blackish; fingernails become diseased more often than toenails; most commonly affected are thumb or Big toe nails; The cause is an infection with the germ Pseudomonas aeruginosa, which are usually due to pre-existing nail damage, such as mechanical stimuli and / or moist environment.
- Nail fold changes
- Nail dystrophy – completely destroyed nail plate.
- Nail loss
- Beau lines – cross grooves of the nails.
- Leukopathies – whitening of the nails in which there is a structural or functional disorder subungual or in the nail bed (e.g., subungual keratosis or circulatory disorder); may occur as a result of an underlying internal disease
- Leukonychia – whitening of the nails, due to structural abnormalities in the nail plate; may occur as part of a syndrome.
- Spoon nails – nails that are transversely and longitudinally concave, resembling a spoon shape.
- Watch glass nails – the nails are distended piston-shaped because of the thickening of the finger end links, larger, roundish in shape and strongly curved outwards
- Yellow-nail syndrome – yellowish discolored nails.
- Half-and-half-nails – nails half brownish-red and white.
- Melanochia striata (Melanonychia striata longitudinalis) – brown, streaky longitudinal coloration, normal variant in dark-skinned people, occurs in more than 70% of the black population over 20 years of age. However, it may also be a malignant melanoma or benign nevus.
* See “Nail Formation Disorders/Causes” for more information.
Warning signs (red flags)
- Subungual hematoma (bruise under fingernail) DD (disease with similar symptoms). Subungual melanoma (acral lentiginous melanoma; melanoma under the fingernail; melanoma = black skin cancer); here, frequent nail destruction, longitudinal melanonychia, i.e., longitudinal pigment streaks (elongated dark streak on a fingernail); this is the first clinical sign of subungual melanoma in 75% of cases
- Melanonychia striata longitudinalis (striate nail pigmentation); dermatoscopic features (→ think: subungual melanoma/nail melanoma):
- Gray or black color
- Irregular brown granular pigmentation of the nail fold (Hutchinson’s sign = increased risk) with or without nail dystrophy
- Spread over at least two-thirds of the nail