Nail Psoriasis – Part 2


Various Presentations 1,2,3,4,5

Nail Pitting:

Pitting is the commonest symptom of nail psoriasis. Pits usually affect the fingernails more commonly than the toenails. They are superficial depressions in the nail plate that indicate abnormalities in the proximal nail matrix (where the nail grows from under the cuticle). Psoriasis affecting the proximal nail matrix disrupts the keratinization of its stratum corneum by parakeratotic cells. Keratinization is the process by which epithelial cells become filled with keratin protein filaments, die, and form tough, resistant structures such as the skin, nails and hair. Pitting results when the keratinization process has been disrupted and the structure of the nail has been compromised allowing some of the cells, as the nail grows and becomes exposed, to be sloughed off forming scattered and coarse pits. Pitting may be arranged in transverse (side to side) or longitudinal rows or it may be randomly scattered. They may be shallow or large to the point of leaving a punched out hole in the nail plate. This is known as elkonyxis.


Clustered                          Scattered                         Linear  



Transverse grooves

Transverse grooves (also known as Beau lines) are formed in the same way as pits. This occurs when the psoriatic lesion affects a wider area of the nail matrix.

    nail_5 nail_6

Subungual hyperkeratosis (Nail plate thickening) and crumbling

An extensive involvement of the entire nail matrix affecting the toenails more frequently than the fingernails. It results from the lifting of the nail plate off the nail bed due to the build-up of cells that have not undergone desquamation (shedding). The resulting accumulated tissue is friable (soft and crumbling) which is susceptible to infection by fungal dermatophytes e.g. Candida albicans (C. albicans) and pseudomonas aeruginosa, leading to either yellow/green discoloration.

nail_7 nail_8

Subungal                                                       Hyperkeratosis          

nail_9 nail_10  

Crumbling                                                 Nail Plate


Leukonychia consists of areas of white nail plate due circumscribed focus of trapped parakeratotic cells within the body of the nail plate. Punctate Leukonychia is characterized by white spots 1-3 mm in diameter occurring singly or in groups and almost exclusively appear on the finger nails.

nail_11 nail_12

Transverse leukonychia                                      Punctate leukonychia

Subacute or chronic paronychia

Psoriatic paronychia usually develops when the periungual skin (around the cuticle) is affected by psoriasis, but it is also commonly seen in psoriatic arthritis with nail involvement. The chronic inflammation causes thickening of the free edge of the proximal nail fold with consecutive loss of cuticle and the attachment of the nail fold’s ventral surface to the underlying nail plate. This allows foreign material such as dirt, microorganisms, or allergenic substances to enter the space beneath the nail fold where they may aggravate inflammation.

nail_13 nail_14

   Subacute                                             Chronic


Acropustulosis is associated with pustular psoriasis and can involve one or all of the digits on the feet and hands. Pustulation of the nail bed and its growth site (matrix) may result in onychodystrophy (malformation) and anonychia (loss of nail). It may also occur as either a part of palmoplantar pustulosis, or acrodermatitis continua of Hallopeau. Usually, there is erythema (redness), swelling and severe discomfort of the entire digit or at the end of the digit. Resorptive osteolysis (resorption of the bone) of the finger or toes may also occur.

nail_15 nail_16

Mild                                                      Mild                                              

nail_17 nail_18

 Severe                                                  Severe

Splinter Haemorrhages and Salmon Spots

Splinter haemorrhages are small linear blackish streaks, about 2-3 mm long, arranged at the distal end of a nail plate. They are caused by the rupture of blood vessels and tracking of the blood along the longitudinal furrows beneath the nail plate. Salmon Spots, also known as “Oil Spots” are a translucent yellowish-red discoloration in the nail bed and can be a small rounded spot or a largish odd shaped spot. 

nail_19 nail_20

     Splinter Haemorrhages                   Salmon Patch

Onycholysis (separation of nail plate from nail bed)

It usually starts at the tip and/or the side(s) of the nail and works backwards. It normally appears white, but occasionally may also appear yellowish. Secondary fungal infections are common.

nail_21 nail_22


Secondary fungal infections, Onychomycosis, may cause a brownish, blackish or even greenish discolouration.

nail_23 nail_24

Onychomycosis is caused by dermatophytes, yeast (C. albicans) and moulds (e.g. Pseudomonas) and is the most common nail disease worldwide with between 6 -30% of the population affected, in PsN up to 70% of sufferers have a secondary fungal infection. Psoriasis often leads to abnormal morphology of the nails. Nails, damaged by psoriasis, lose their natural protective barrier and are therefore more susceptible to fungal infections. Researchers have found that dermatophytes more often cause toenail onychomycosis. Yeasts were isolated in a higher percentage from fingernails. The most common pathogens are Trichophyton rubrum, Trichophyton mentagrophytes and C. albicans. A correlation was observed between psoriatic change of fingernail plate – Nail Psoriasis Severity Index (NAPSI) and positive mycology.5


  • Dogra A.and  Kaur Arora A.: Nail Psoriasis: The Journey So Far; Indian J Dermatol. 2014 Jul-Aug; 59(4): 319–333.
  • Sánchez-Regaña M. and Umbert P.; Diagnosis and Management of Nail Psoriasis; Actas Dermosifiliogr. 2008;99:34-43
  • Ghosal A, Gangopadhyay DN, Chanda M, Das NK. Study of nail changes in psoriasis. Indian J Dermatol. 2004;49:18–21.
  • Reich K. Approach to managing patients with nail psoriasis. J Eur Acad Dermatol Venereol. 2009;23(Suppl 1):15–21. [PubMed: 19686381]
  • Zisova L. et al. ; Onychomycosis in patients with psoriasis; Mycoses 55, 143–147 doi:10.1111/j.1439-0507.2011.02053.

Psoriatic Nails – Part 1


Psoriasis can affect both finger nails and the toe nails (Psoriatic Nails). The percentage of those with psoriasis who have nail involvement is thought to be 50%. For some unknown reason the finger nails are more often involved than toe nails. In most cases people with psoriasis have concurrent nail psoriasis; however, in 5- 10% of cases the nails only may be affected. In one study it was found that the frequency of nail changes in patients with Koebner’s phenomenon was 56%, whereas as in those without Koebner’s phenomenon it was only 29%. Nail psoriasis is approximately 10% more common in males than in females and is positively associated with higher bodyweight.1

Nail psoriasis is characterised clinically by manifestations on the fingernails and toenails. The mean delay of onset for nail dystrophies occurs in individuals with psoriasis between 9 and 11.5 years, explaining the lower prevalence of nail psoriasis in children.2 There may be involvement of only a single nail or of all nails and over time is associated with severe nail destruction or total nail loss.

Clinical Forms of Nail Psoriasis 3,4,5

  1. Psoriasis on the Nail Matrix and Plate
  • Pits or pitting, or dimples – Pitting is the result of the loss of cells from the surface of the nail. (see pictures 1-4 Part 2) Pitting occurs in approximately 70% of psoriatic nails.
  • Trachyonychia – rough (sandpapered) accentuated linear ridges (longitudinal striations) on the nails
  • Leukonychia – white nails or milk spots
  • Beau Lines – deep transverse (side to side) linear depressions, lines or trenches across the nails
  • Red lunulae – is the white half-moon–shaped area located at the base of fingernails and toenails; it is the only visible part of the nail matrix. The lunula becomes red when the capillaries under the nail are congested. staff.

“Blausen gallery 2014”. Wikiversity Journal of Medicine. 

DOI:10.15347/wjm/2014.010. ISSN20018762

  1. Psoriasis of the Nail Bed
  • Onycholysis – the separation of the nail plate from the underlying nail bed and hyponychium (commonly known as the “quick”)
  • Subungal hyperkeratosis – excessive proliferation of the nail bed and hyponychium where a chalk like substance builds up.
  • Oil spots or salmon patches – these are the only lesions that are exclusive to nail psoriasis; they appear as round or oval yellowish brown/orange coloured areas in the centre of the nail plate
  • Splinter haemorrhages – small black lines that run from the tip of the nail to the cuticle as the result of the capillaries (very small blood vessels) between the nail and the skin bleeding.
  1. Paronychia

    An infection of the skin around the fingernails and toenails usually caused by a bacterial and/or fungal infection.

  1. Acropustulosis – characterised by pustular eruptions beginning in the tips of fingers and toes.

          Digits become swollen and malformed.

Psoriatic arthritis initially may present with only a few swollen joints. It is often common for just a single finger or toe to be noticeably swollen. Some people feel stiff when they wake up. As they move around, the stiffness fades. Sausage-like swelling in the fingers or toes (dactylitis), pain in and around the feet and ankles, especially tendinitis in the Achilles tendon or Plantar fasciitis in the sole of the foot and changes to the nails, such as pitting or separation from the nail bed are all indicative of Psoriatic Arthritis. More than 80% of patients with psoriatic arthritis will present with psoriatic nail lesions.

Researchers found that the nail and the enthesis (connective tissue – that directly attaches to the bone, via the distal interphalangeal (DIP) joint extensor tendon) are key players in the pathophysiology of nail psoriasis. Specifically, they found that the extensor tendon, at its enthesis, is able to send superficial fibres, which contribute to the formation of thick tissue surrounding the finger bones. This links the dense fibrous connective tissue from the nail plate to the tissue surrounding the finger bones and indirectly to the extensor tendon. The study suggested that there is an association between the DIP joint arthritis and nail disease due to the close interaction between the nail, joint and its associated tendons and ligaments. This is supported by the fact that although the nail system has no neural component, 50% of patients with nail psoriasis observe mild to severe pain and restricted mobility of the fingers.2

Many patients find that it becomes progressively more and more difficult and painful to use the fingers for gripping cutlery, pens and tools and performing tasks such as buttoning clothes, buttering toast, writing, typing etc., which are actions that we take for granted, become tasks that they can no longer do. As well as daily day to day activities many patients find that psoriatic nails also impact upon their sporting activities such as tennis, golf, swimming etc.



  • Dogra A.and  Kaur Arora A.: Nail Psoriasis: The Journey So Far; Indian J Dermatol. 2014 Jul-Aug; 59(4): 319–333.
  • Tirant M. et al.; Nail Psoriasis In an Adult Successfully Treated With a Series of Herbal Skin Care Products Family – A Case Report; Journal Of Biological Regulators & Homeostatic Agents; 30, no. 2 (S3), 21-28 (2016)
  • Sánchez-Regaña M. and Umbert P.; Diagnosis and Management of Nail Psoriasis; Actas Dermosifiliogr. 2008;99:34-43
  • Ghosal A, Gangopadhyay DN, Chanda M, Das NK. Study of nail changes in psoriasis. Indian J Dermatol. 2004;49:18–21.
  • Reich K. Approach to managing patients with nail psoriasis. J Eur Acad Dermatol Venereol. 2009;23(Suppl 1):15–21. [PubMed: 19686381]