Anonymity (overview) Q84.30

Complete or partial(microonychia, hyponychia, onychoatrophy), acquired or congenital "naillessness" on one or more finger(s) and/or on one or more toe(s).

Acquired anonychia:

• Traumatically induced
• Tinea unguium
• Lichen planus
• Chronic eczema
• Psoriasis vulgaris
• Acrodermatitis continua suppurativa
• Syphilis
• Erythroderma of different genesis
• Drug-acquired in prenatal phenytoin ingestion
• Anonychia due to invasive tumor growth (e.g. acrolentiginous melanoma)

Congenital anonychia: A number of different syndromes have been described:

• Anonychia congenita: In autosomal recessive congenital anonychia (OMIM 206800), congenital anonychia is the leading symptom (no hypoplasia of the bony terminal phalanges). Mutations in the RSPO4 gene, which codes for R-spondin 4, a component of the Wnt signalling pathway, are detectable.
• In mammary finger-nail syndrome, nails are absent with hypoplasia or complete absence of the end phalanges.
• In Cooks syndrome, nail dystrophy progresses to anonychia of the ring and little finger.Furthermore, there is digitization of the thumb.
• In anonychia-ectrodactyly syndrome, the finger abnormalities are asymmetrical, including the absence of 1 or more fingers.
• 20-nail dystrophy
• Nail-patella syndrome (anonychia, hyponychia, onychoschisis, triangular lunula. Most affected are thumb and index finger nails; toenails are almost always normal).
• Isolated anonychia-onycholysis (Nail disorder, nonsyndromic congenital 9: this is an autosomal recessive nail dystrophy. The nails appear normal at birth; in the first decade of life onycholysis of the toenails leading to anonychia).

In the case of acquired anonymity: treatment of the underlying disease, see there.

1. Afsar FS et al (2014) Total congenital anonychia. Pediatric dermatol 31:743-744
2. Babu S et al (2012) Anonychia due to prenatal phenytoin exposure. J Assoc Physicians India 60:64
3. Balta I et al (2013) A case report on autosomal recessive total congenital anonychia. Pediatric Dermatol 30: e268-269
4. de Lau WB et al (2012) The R-spondin protein family. Genomes Biol.13:242
5. Lam C et al (2013) Images in clinical medicine. Epidermolysis bullosa acquisita. N Engl J Med 368:e17
6. Khan TN et al (2012) Novel missense mutation in the RSPO4 gene in congenital hyponychia and evidence for a polymorphic initiation codon (p.M1I). BMC Med gene 13:120