Nail Disorders

Psoriasis is a chronic inflammatory skin condition that can also affect the nails (please see our Psoriasis section). Nail psoriasis is a subtype of psoriasis and can manifest prior to any evidence of the cutaneous disease in up to 10% of cases. Epidemiology of psoriasis in hard-to-treat body locations: data from the Danish skin cohort – PubMed. It is highly prevalent, affecting up to 80% of patients with plaque psoriasis and 97% of patients with psoriatic arthritis (joint involvement). Nail Psoriasis: Diagnosis, Assessment, Treatment Options, and Unmet Clinical Needs – PubMed. It is associated with significant disease burden and negative impact on the quality of life. Treatment of Nail Psoriasis – PubMed

Nail psoriasis typically presents with key clinical features according to the structure that is involved within the nail unit. When psoriasis is present within the nail matrix, pitting (studded depressions), Beau lines (horizontal depressions or ridges in the nail plate) and crumbling of the nail plate are often seen. Psoriasis of the nail bed presents as oil-drop discoloration (translucent yellow-red discolouration in the nail bed), splinter haemorrhages (red linear streaks on the nail plate), subungual hyperkeratosis (thickening and scaling skin cells under the nail plate) and onycholysis (separation of the nail plate from the underlying nail bed) Nail Psoriasis: A Review of Treatment Options – PMC    

The diagnosis of nail psoriasis is made clinically with the aforementioned clinical signs as discussed above. Investigations may be used in atypical presentations to exclude other potential causes. A nail biopsy of the nail matrix or nail bed may be used to identify the characteristic findings of psoriasis but is generally unnecessary. Role of tangential biopsy in the diagnosis of nail psoriasis – PubMed. 

The treatment of nail psoriasis is often time-consuming and challenging, with an uncertain outcome and often with relapses. Treatment options can include topical or systemic therapy, which is based on the severity or extent of the disease. In mild disease, changes are limited to 1 or 2 nail beds with no functional impairment or systemic involvement. Where as moderate to severe disease is classified as changes beyond 2 nails with functional impairment and/or systemic involvement Nail Psoriasis: A Review of Treatment Options – PMC

Topical treatments are often the first choice, but their effectiveness is limited to nail bed psoriasis; they are not very effective on nail matrix psoriasis because they do not penetrate the nail plate. Corticosteroids, both creams and intralesional applications and are effective in reducing inflammation, nail pitting, thickening and onycholysis. Optimal management of nail disease in patients with psoriasis – PMC. Other topical treatment options include Vitamin D analogues such as calcipotriol, calcitriol and tacalcitol, that work by slowing the rapid growth of skin cells, reducing inflammation, thickening, pitting and discoloration. Optimal management of nail disease in patients with psoriasis – PMC. These therapies can be combined to enhance the effectiveness, improving penetration through the thick nail structure and tackling both the inflammatory and hyperproliferative aspects of the disease.

Systemic therapies are recommended in patients with skin psoriasis or joint involvement or in cases of moderate to severe nail psoriasis that have failed to respond to topical therapies. Optimal management of nail disease in patients with psoriasis – PMC. Treatment consists of the use of DMARD’s (methotrexate, cyclosporine) that are effective in treating nail disease  Evaluation of the efficacy of methotrexate and cyclosporine therapies on psoriatic nails: a one-blind, randomized study – PubMed and in refractory and severe cases the use of biologics can be considered but, due to potential side effects, is usually a last resort Infliximab induction and maintenance therapy for moderate-to-severe psoriasis: a phase III, multicentre, double-blind trial – PubMed

Paronychia is primarily an infection of the proximal and lateral fingernail and toe nail folds, including the tissue that borders the root and side of the nail. There are both acute (less than 6 weeks) and chronic (more than 6 weeks) presentations with infectious and non-infectious causes. Bacterial infection (staphylococci aureus) makes up the majority of cases especially acutely Acute and Chronic Paronychia Revisited: A Narrative Review – PMC. It is more commonly seen in women than it is in men, with a 3 to 1 ratio respectively. Risk factors include frequent, prolonged exposure of the hands to water or irritants, trauma to the nail fold and in patients with underlying conditions such as diabetes and immunosuppression Acute and Chronic Paronychia | AAFP   

Patients with acute paronychia present with a 2–5-day history of erythema, edema, pain and marked tenderness in a single digit along the lateral proximal nail fold with often evidence of purulent discharge Paronychia – StatPearls – NCBI Bookshelf

Patients with chronic paraonychia presents with erythema, pain and swelling around the nail fold of greater than a 6-week duration. Symptoms are not as severe as with acute paronychia hence patients often present later. It generally involves more than one digit, where a single digit is involved, other potential causes including malignancy should be excluded Acute and Chronic Paronychia | AAFP. It is commonly caused by mechanical or chemical irritants though infection (usually fungal/candida) can still be attributed to chronic cases Paronychia – StatPearls – NCBI Bookshelf   

The diagnosis is typically made on clinical grounds by examination of the hands along with the patients history. Investigations are usually reserved for atypical presentations or severe symptoms and may include, imaging (in the case of severe infections where abscess formation is considered, osteomyelitis, or malignancy) cultures (used in severe or refractory infections to target treatment) Microbiological analysis of acute infections of the nail fold on the basis of bait thread test – PMC     

The treatment of paronychia is specific to the underlying cause. For acute paronychia, treatment is determined by the degree of inflammation. In mild cases, warm soaks, topical antibiotics creams (Mupirocin, gentamicin, bacitracin, neomycin) alone or in combination with a topical corticosteroid (betamethasone) is often effective for the treatment of uncomplicated bacterial paronychia Acute paronychia: comparative treatment with topical antibiotic alone or in combination with corticosteroid – PubMed. For persisting cases, oral antistaphylococcal antibiotic therapy should be started Scenario: Management | Management | Paronychia – acute | CKS | NICE. Where abscess formation has developed these should be surgically managed to allow for drainage Scenario: Management | Management | Paronychia – acute | CKS | NICE.   

The treatment of chronic paronychia includes; avoiding exposure to contact irritants, impeding inflammation, allowing the cuticle to heal through preventative measures (please see attached Table – PMC ), medical management and/or surgical intervention. The use of corticosteroids are considered the mainstay of therapy and are considered superior to topical antibiotics and systemic antifungals with there use reserved generally in the case of fungal (candida) infection Acute and chronic paronychia of the hand – PubMed. Surgical management is typically reserved for patient with well-formed abscess and/or failure to respond to medical intervention of at least 6-month duration Acute and Chronic Paronychia Revisited: A Narrative Review – PMC

Melanonychia is a common cause of nail discolouration, accounting for nearly half of all cases seen in a dermatology clinic. Distinct Patterns and Aetiology of Chromonychia – PubMed. Longitudinal melanonychia is the most common pattern, with a brown or black discoloration extending from the nail matrix to the free edge. Transversal or total melanonychia are rarely encountered. Melanonychia – Clues for a Correct Diagnosis – PMC. This discolouration is due to increased melanin production with two potential mechanisms.

1. Melanocytic activation refers to increased melanin production from a normal number of activated melanocytes (cells of the skin responsible for skin colour) in the nail matrix. There are a number of potential underlying causes, including physiological (more commonly seen in individuals with black skin, Asians and Hispanics), trauma, infections, pregnancy, inflammatory skin disorders (psoriasis), systemic causes (Addison disease, Cushing disease), iatrogenic causes (medication, X-ray exposure), nutritional deficiencies and tumours Melanocytic Lesions of the Nail Unit – PMC     
2. Melanocyte proliferation refers to increased melanin production secondary to an increased number of melanocytes in the nail matrix. There are three types of longitudinal melanonychia in this category: benign melanocytic hyperplasia within the nail matrix (nail matrix nevi/moles or nail matrix lentigo/freckle) and melanoma. The former two conditions are benign and are more commonly seen in children and adults, respectively, while the latter condition is malignant Melanocytic Lesions of the Nail Unit – PMC

The vast majority of longitudinal melanonychia are caused by benign conditions however malignancy due to subungual melanoma or squamous cell carcinomas are also possibilities that must be excluded due to the poor prognosis with delayed diagnosis Melanonychia – PMC.     

The underlying cause (benign/malignant) is often diagnosed through a combination of clinical features (The ABCDEF mnemonic helps identify risk factors for malignancy and can be accessed here: Melanonychia – PMC), dermoscopy and biopsy Melanonychia – PMC. As the clinical diagnosis of melanonychia is frequently difficult on clinical and dermoscopy assessment alone, biopsy is the gold standard and often necessary to make a definitive diagnosis. Longitudinal Melanonychia: How to Distinguish a Malignant Condition from a Benign One – ScienceDirect.

The treatment of melanonychia is specific to the underlying cause. Benign causes (race, ethnicity, harmless moles) do not necessitate treatment, though monitoring for changes in their appearance is recommended. Patients should be counselled for self-examination and to report any morphological changes. The ABC rule for clinical detection of subungual melanoma – PubMed.  In the case of underlying infections, these are most commonly treated with antifungal medications, iatrogenic causes may include changes in medication where possible, addressing underlying medical conditions (systemic disease) and addressing any nutritional deficiencies may cause regression of pigmentation Melanonychia: Etiology, Diagnosis, and Treatment – PMC. In the cases of malignancy, most commonly due to subungual melanoma, these are often managed surgically with wide local excision or digit amputation depending on the grade and depth of the lesion with or without sentinel lymph node mapping/biopsy The Prognosis of Nail Apparatus Melanoma: 20 Years of Experience from a Single Institute – PubMed.

Nail plate brittleness or splitting is a common complaint seen in dermatology clinics, affecting up to 20% of the population, especially women over the age of 50, with nail splitting being more prevalent in the hands than in the feet Incidence of brittle nails – PubMed.

Brittle nails manifest either through factors that alter nail plate production and/or factors that damage the nail plate itself. The condition is characterised by nails that flake, crumble, peel or break easily. The main clinical features are onychoschizia (horizontal, lamellar splitting of the free nail edge), onychorrhexis (longitudinal ridging, splitting or brittleness of the free nail edge) and keratin granulation, due to an accumulation and clumping of keratin on the nail plates (superficial, small white/yellow patches and striations) Pathogenesis, Clinical Signs and Treatment Recommendations in Brittle Nails: A Review – PMC.

The condition is not always painful, but pain can occur from deep splitting or if any object were to catch the nail plate itself. They can cause significant cosmetic or functional impairments for patients with even associated effects on mental health. Perception of brittle nails in dermatologic patients: a cross-sectional study – PubMed. 

Brittle nails have two forms and can have either ‘idiopathic courses’ or ‘secondary courses’ due to an array of different medical conditions.

• Idiopathic, basically means in the absence of a definable medical reason. This is by far the most common subtype and is attributed to postmenopausal women and an increasing age and is almost exclusively seen in the fingernails. A possible explanation being linked to dehydration and reduced lipid production as we age, both considered important for normal nail plate synthesis Age-associated changes in integral cholesterol and cholesterol sulfate concentrations in human scalp hair and finger nail clippings – PubMed.
• Secondary, refers to the presence of an underlying medical condition that can be attributed to the nail disease. This includes,

1. inflammatory nail disorders such as patients with psoriasis with up to 50% of these patients have brittle nails Nail involvement as a negative prognostic factor in biological therapy for psoriasis: a retrospective study – PubMed). Other causes include eczema, lichen planus and alopecia areata.
2. Infection, superficial white onychomycosis, is a cause of nail brittleness due to damage of the nail plate secondary to keratin digestion by the fungi. Nail digital dermoscopy (onychoscopy) in the diagnosis of onychomycosis – PubMed.
3. Systemic diseases and medications. Patients with endocrine disorders (hypothyroidism) commonly have concurrent brittle nails Brittle Nails and Hair Loss in Hypothyroidism – PubMed. As do patients with impaired peripheral circulation (diabetes, arteriosclerosis, chronic anaemia and neurological conditions). Exposome Impact on Nail Health – PMC. Certain systemic medications used for treating cancers or chronic infections can be attributed to the disease as can severe vitamin deficiencies (biotin, iron, vitamin C and Vitamin D) crucial for keratin production. Modulation of linear nail growth to treat diseases of the nail – PubMed   
4. Traumas and alteration of nail hydration. Trauma to the nail plate can be caused by mechanical forces; these include onychotillomania and onychophagia (nail biting) or exposure to solvents/solutions that affect the normal keratin homeostasis of the nail plate Exposome Impact on Nail Health – PMC. Manicures affect nail hydration are also a subsequent cause Exposome Impact on Nail Health – PMC

For the majority of patients presenting to the dermatology clinic with brittle nails, they have an idiopathic cause. Treatment for these patients consists of supplementation with biotin (vitamin B7) and amino acids (especially cysteine) The Role of Vitamins and Minerals in Hair Loss: A Review – PubMed and the use of daily nail moistures (petrolatum jelly and lanolin) to lock in moisture and to improve nail hydration Pathogenesis, Clinical Signs and Treatment Recommendations in Brittle Nails: A Review – PMC. Patients should also be advised where possible to avoid repeated immersion in water and the use of detergents and soaps. Wet working conditions increase brittleness of nails, but do not cause it – PubMed

Secondary nail brittleness should be treated, where possible, on addressing the underlying cause along with local treatment. Local treatment is as discussed previously. The treatment of underlying causes may include the treatment/management of dermatological/systemic conditions. Treating underlying infectious causes and stopping/changing medications where possible Pathogenesis, Clinical Signs and Treatment Recommendations in Brittle Nails: A Review – PMC.