Continuing Education Activity

Psoriasis is a common and chronic inflammatory disease involving skin, nails, and joints. Nails are the visible parts of the body and it affects the quality of life with social and psychological impacts. Due to the slow growth pace of nails, its treatment is prolonged and often with incomplete recovery, which further enhances the stress and anxiety of the patients. This activity reviews the clinical presentation, evaluation, and treatment of nail psoriasis and highlights the role of the interprofessional team in evaluating and treating patients with this condition.

Objectives:

• Describe the pathophysiology of psoriasis of nails.
• Outline the importance of history and physical examination of nail psoriasis.
• Explain the management options of psoriasis nails according to the severity of the disease.
• Explain the importance of improving care coordination amongst the interprofessional team to improve outcomes for patients with psoriasis of the nails.

Introduction

Psoriasis is a common chronic inflammatory condition of the skin, which also has nails and systemic involvement. Psoriatic involvement of the nail bed or nail matrix results in nail psoriasis.[1] Nail involvement is a visible indicator to predict future joint inflammatory damages and disease activity. Nail psoriasis can manifest clinically as a wide variety of nail changes, like nail discoloration, subungual hyperkeratosis, pitting and onycholysis, depending upon the part of the nail units affected. Patients with psoriatic nails have impaired quality of life due to the appearance of nails, and significant morbidity and functional impairments may arise in large cases. Its management is challenging because it is long term, and often not satisfying the patients leads to depression, which further deteriorates the condition. Patient education with explaining the prognosis and outcomes of the treatment is the most important aspect.[2]

Etiology

The exact etiology of nail psoriasis is unclear, but multiple factors may contribute to being the etiology of nail psoriasis, which include genetic, immunological, and environmental factors. However, dysregulation of innate immunity is thought to be the stronger associated factor, while genetic factors are not well understood. Family history is common, and human leukocyte antigens (Cw6, B13, B17) are associated with it.[3]

Epidemiology

Nail psoriasis affects both children and adults. It equally affects males and females and has increase prevalence with increasing age. Nail Psoriasis mostly develops in association with cutaneous psoriasis and psoriatic arthritis with a prevalence of 10% to 55% and 80% to 90%, respectively. Nail psoriasis may develop as a sole manifestation. The involvement of nail in a patient with cutaneous psoriasis is concurrent or develops after the onset of cutaneous symptoms.[2]

Pathophysiology

Nail psoriasis usually results from psoriatic inflammation involving the nail bed or nail matrix. The matrix of the nail is mainly responsible for nail plate formation and is located beneath the proximal nail fold. The superficial part of the nail plate is formed from the proximal nail matrix while the deep part is formed from the distal nail matrix. The nail bed lies directly beneath the nail plate and plays a significant role in the adherence of the nail plate to the nail bed.[4] Clinical features related to nail matrix involvement are nail Pitting, red spots in the lunula, leukonychia, and crumbling of the complete nail plate. The involvement of the nail bed manifests clinically as Onycholysis, splinter hemorrhages, subungual hyperkeratosis, and oil drop discoloration.[1]

Genetic contributions to the formation of nail psoriasis are still uncertain. Psoriatic nail disease may, however, align more closely with innate immunity dysregulation. Thus, psoriatic nail disease can contribute differently to innate and adaptive immunity than the disease limited to the skin.

Histopathology

Histopathological findings of nail psoriasis are similar to cutaneous psoriasis, and it includes mild to moderate hyperkeratosis, spongiosis, and focal hyperkeratosis. Other prominent features are neutrophilic inflammatory infiltrate, hypergranulosis, and papillomatous epidermal hyperplasia. Papillary dermis shows dilated tortuous inflamed capillaries. The hyponychium shows the loss of the granular layer while there is hypergranulosis in the nail bed and matrix of the nail.[4]

History and Physical

As nail psoriasis is strongly associated with cutaneous psoriasis and psoriatic arthritis, one should take the proper history of the skin lesions and joint-related symptoms like swelling and pain. Most of the patients with psoriatic arthritis present with involvement of distal interphalangeal joints. Presentation of nail psoriasis alone without any cutaneous and joint involvement is always a diagnostic challenge in many cases.[5]

A patient of nail psoriasis may have either one or multiple affected finger and toenails. The psoriatic nail may have more than one clinical manifestation in a single nail depending upon the part of the nail apparatus affected. The common clinical manifestations of nail psoriasis are nail Pitting, subungual hyperkeratosis, onycholysis, and oil drop discoloration. However, nail plate crumbling, red spots in lunula, leuconychia, and splinter hemorrhages are other features. Patients may have manifestations like onychorrhexis and beau lines, which are longitudinal ridges with distal nail plate splitting and transverse grooves, respectively.

A complete thorough examination of the skin, including the scalp and anogenital area, is important to assess the extent and severity of the condition.[6][4] Nail psoriasis is a common feature of patients presenting with psoriatic arthritis, and it is prudent to assess signs of psoriatic arthritis. Examine for the swelling and tenderness of the joints, especially distal interphalangeal joints of both feet and hands and swelling of digits.

Evaluation

Nail psoriasis is usually diagnosed on a clinical basis by a proper history and complete physical examination. Fungal infection testing is also necessary in few cases to rule out onychomycosis. The biopsy is not necessary except for selective cases where the diagnosis is uncertain, and biopsy of the nail bed or nail matrix is taken and sent for histological examination.[7]

Treatment / Management

Patient with nail psoriasis is treated with either topical or systemic therapy. Other options include biologic agents, photodynamic therapy, phototherapy, intense pulsed light, and lasers treatment. The treatment options mainly depend upon the severity and extent of disease. The various other factors which need to be considered for treatment options are the age of the patient, comorbidities, profession, concomitant skin and joint involvement, impact on the quality of life, patient preference, and cost of treatment.[8]

Mild nail psoriasis:

• In mild cases, where the disease is limited to one or two nails with no significant symptoms, topical therapy is the best option. Topical corticosteroids and topical vitamin D analogs are first-line while topical tacrolimus and topical tazarotene are the second-line therapy. Systemic therapy is limited to patients who did not respond to topical therapy.

Moderate to severe nail psoriasis:

It is considered when nail psoriasis is associated with severe nail dystrophy that usually involves more than two nails with significant functional impairment.[9][10]

• First-line therapy: A biologic agent is an effective first-line treatment to treat moderate to severe psoriasis of the nail. The common biological agents use to treat nail psoriasis are Eternacept. Adalimumab .infliximab) (TNF alpha inhibitors), Ustekinumab (inhibitor of p40 subunit of IL-12/23), and Secukinumab, Ixekizumab (a monoclonal antibody inhibiting the IL-17A ligand).

This therapy is very effective, but few patients don’t prefer this option due to cost and affordability issues. These biological agents increase the risk of fungal skin infections.[11]

• Second-line therapy: The second-line therapy for moderate to severe psoriasis includes topical therapies, (topical tacrolimus, topical tazarotene, topical calcipotriol, and potent topical corticosteroid )intralesional corticosteroids, pulsed dye LASER. Systemic therapies are  Methotrexate and apremilast.[12]

Additional therapies need further recommendations to include oral tofacitinib, topical cyclosporine, topical indigo naturalist, oral acitretin, oral cyclosporine, and phototherapy.

Differential Diagnosis

• Onychomycosis: The changes of onychomycosis resemble nail psoriasis, and sometimes it is difficult to distinguish between the two. Nail pitting, onycholysis, and oil drop sign are the main features of nail psoriasis. Onychomycosis can be diagnosed by fungal culture, nail clipping with periodic acid Schiff( PAS)and potassium hydroxide (KOH) preparations.[1]

• Alopecia areata: It usually appears as linear ridging, nail pitting, longitudinal nail fissuring, and some other nail abnormalities along with non-scarring patchy alopecia of the scalp or other body areas.

• Lichen planus: Nail involvement presents as thinning of nails with ridges and grooves of the nail plate sometimes scarring of cuticle occur leading to pterygium formation. Lichen planus also involves the mucosa or skin. The skin manifestations of lichen planus are itchy, purple, polygonal papules or plaques.[13]

• Pityriasis Rubra pilaris: It is an uncommon skin disorder that usually presents as hyperkeratotic follicular papules, orange-red plaques with fine scales, and hyperkeratosis of palms and soles. The nails usually become thickened, and distal edges often show splinter hemorrhages.

Prognosis

Patients with nail psoriasis have a chronic and protracted course with periods of improvement and worsening with a greatly profound effect on the quality of life.patient may have periods of normal nails without alteration.patients of psoriasis with nail involvement have a poor prognosis. nail trauma may be the trigger and exacerbating factor for nail psoriasis.treatment with topical agents in case of mild disease and systemic therapy in moderate to severe disease may alter the disease process in the long run but on the cost of side effects and complications.[11]

Complications

The patient suffering from nail psoriasis may develop complications either due to the disease process itself or as a result of drugs used in treatment. The major complications can be grouped into functional disability, psychological distress, and infections, including bacterial and fungal infections.acute and chronic paronychia and onychomycosis.

Deterrence and Patient Education

Nail psoriasis is a chronic disease process, treatment may be prolonged, and education of patients is an essential part of management.[14] The treatment is prolonged due to a slow nail growth pace, which leads to a prolonged course of treatment. Proper communication with the patient may encourage reasonable perceptions of treatment outcomes, and it may facilitate therapy adherence. Patients need to follow gentle hand and foot care measures that may help to decrease the symptoms. These general measures include the regular application of emollients, regularly trimming of the nails, keep them dry and protection from trauma to prevent Koebner phenomena. In addition, they need to take photographs of nails periodically as these pictures would help to assess the treatment response.[5]

Enhancing Healthcare Team Outcomes

Nail psoriasis is a difficult condition to manage, and its management is best by an interprofessional team.[1]

• Consider the impact of nail psoriasis on psychosocial distress and quality-of-life and remember that it may lead to anxiety or psychiatric disease.
• The dermatologist and pharmacist can help to promote the appropriate use of topical and systemic agents.
• Patient education and skincare measures would help to manage the disease effectively.
• Nail psoriasis and psoriatic arthritis frequently coexist, a team-based approach with the involvement of rheumatologist and orthopedics is mandatory to treat such patients.

Even though sometimes primary clinicians manage these patients, it is best to refer these patients to the dermatologist. Dermatology specialty-trained nurses can also help by counseling the patient, providing direction on medical management, and monitoring and charting treatment progress. A pharmacist should also be on the case, with assistance in selecting the most appropriate agents, verifying dosing, offering patient education, and performing medication reconciliation, informing the prescriber of any issues encountered. Close communication between interprofessional team members is vital to achieving desired outcomes.[4]