What is nail psoriasis?

Nail psoriasis is psoriasis infiltrating different parts of the nail resulting in a variety of nail changes. While nail involvement affects more than 80% of people with plaque psoriasis, it occurs as an isolated disease in only 5% of people with any type of psoriasis.^1,2 Some studies show that psoriatic arthritis has been found to be more strongly associated with nail psoriasis than psoriasis affecting only the skin.³

Symptoms

In people with nail psoriasis, one nail, multiple nails, both fingernails and toenails, fingernails only, or toenails only may be affected.⁴ Some physical changes in the nails include:

• Pitting: Small depressions in the nail plate, ‘pits’
• Leukonychia: White lines or dots across the nail plate
• Nail plate crumbling: Disintegration of the nail
• Oil drop or salmon patch: Translucent yellow-red patches in the nail bed
• Onycholysis: Separation of the nail plate from the nail bed, starting at the tip of the finger
• Subungual hyperkeratosis: Accumulation of excessive skin cells, with a grey-white appearance, under the nail
• Splinter hemorrhages: Faint red lines in the nail bed from small blood vessels bleeding

Diagnosis

Nail psoriasis is clinically diagnosed, meaning that your doctor will take a thorough medical history and do a full physical examination, including taking a close look at your skin and nails. They may ask you questions about when or how you first noticed your nail changes, what other symptoms you have, and if any other parts of your body are affected. Because of the close association of nail psoriasis with plaque psoriasis and psoriatic arthritis, a close examination of the skin and joints is important. Your healthcare provider will also want to rule out a fungal infection of the nail, as it can often be difficult to distinguish from nail psoriasis.⁵

Treatment

Any disease involving the nails will require a longer course of treatment because of how slowly the nails grow. Once the nail plate is formed, it does not change. Rather, treatments of nail psoriasis aim to allow the new nail to grow out normally. Therefore, it is important to understand that your nail symptoms and physical findings will not disappear right away with treatment, but with consistency and adherence to your prescribed treatment course, you will slowly begin to see results. In general, fingernails take 6 to 12 months to grow out whereas toenails take 12-18 months to grow out.

Regardless of the severity of your nail psoriasis, some general principles of conservative treatment include avoiding trauma to the nails (e.g. manicures, nail-biting), keeping nails trimmed, wearing protective gloves during exposure to chemicals, drying nails thoroughly after washing hands, and applying lotions and moisturizers regularly.⁶ Medical therapy for nail psoriasis that only involves a few nails can include topical corticosteroids, topical vitamin D analogs, topical calcineurin inhibitors, intralesional steroid injections, or phototherapy. Moderate-to-severe nail psoriasis with associated skin or joint systems may require oral therapies or injectable biologics.⁶

References

1. Pasch MC. Nail Psoriasis: A Review of Treatment Options. Drugs. 2016;76(6):675-705.
2. Dogra A, Arora AK. Nail psoriasis: the journey so far. Indian J Dermatol. 2014;59(4):319-333.
3. Wilson FC, Icen M, Crowson CS, McEvoy MT, Gabriel SE, Kremers HM. Incidence and clinical predictors of psoriatic arthritis in patients with psoriasis: a population-based study. Arthritis Care Res . 2009;61(2):233-239.
4. de Jong EM, Seegers BA, Gulinck MK, Boezeman JB, van de Kerkhof PC. Psoriasis of the nails associated with disability in a large number of patients: results of a recent interview with 1,728 patients. Dermatology. 1996;193(4):300-303.
5. Haneke E. Nail psoriasis: clinical features, pathogenesis, differential diagnoses, and management. Psoriasis (Auckl). 2017;7:51-63.
6. Tan EST, Chong W-S, Tey HL. Nail psoriasis: a review. Am J Clin Dermatol. 2012;13(6):375-388.