Nail disorders are difficult to treat and often frustrating both for patients and clinicians. Because of the slow growth rate of the nail plate and the difficulty of getting the drug actives to penetrate the nail tissues, it is usually necessary to wait several months before seeing the results of treatments. This delay often leads to discontinuation of therapy by the patients. This article therefore helps clinicians to find the right treatment of the 5 most common nail disorders (brittle nails, onycholysis, paronychia, psoriasis, and onychomycosis) and provides practical tips that might improve patients’ compliance.
Key points
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Nail disorders are difficult to treat and often frustrating for both patients and clinicians.
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Knowledge of the disease to be treated and the patient’s status are important for the choice of the best treatment option.
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The nail plate is a dead structure and clinicians cannot act on it. Treatment should be focused on the new growing nail.
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When facing a nail disorder, consider the presence of more than 1 disease at the same time (eg, psoriasis and onychomycosis/paronychia and onychomycosis/psoriasis and fragility).
Introduction
Nail disorders are difficult to treat and often frustrating for both patients and clinicians. Because of the slow growth rate of the nail plate (3 mm/mo for fingernails and 1.5 mm/mo for toenails) and the difficulty of getting the drug actives to penetrate the nail tissues, it is usually necessary to wait several months before seeing the results of treatments. This delay often leads to discontinuation of therapy by the patients.
This article therefore helps clinicians (dermatologists and general practitioners) to find the right treatment of each of the 5 most common nail disorders and provides practical tips that might improve patients’ compliance.
Introduction
Nail disorders are difficult to treat and often frustrating for both patients and clinicians. Because of the slow growth rate of the nail plate (3 mm/mo for fingernails and 1.5 mm/mo for toenails) and the difficulty of getting the drug actives to penetrate the nail tissues, it is usually necessary to wait several months before seeing the results of treatments. This delay often leads to discontinuation of therapy by the patients.
This article therefore helps clinicians (dermatologists and general practitioners) to find the right treatment of each of the 5 most common nail disorders and provides practical tips that might improve patients’ compliance.
Brittle nails
Nail fragility is a condition that almost exclusively affects fingernails. It may be idiopathic or the consequence of factors that alter nail plate production and/or damage the already keratinized nail plate (trauma, dermatologic/systemic disorders, nutritional deficiencies, drug intake).
Scanning electron microscopy studies indicate that idiopathic nail brittleness is associated with an intrinsic defect in the intercellular cement that holds together nail plate keratinocytes, with a disorganized protein and lipid structure and with a disorganized orientation of keratin filaments (in normal conditions, keratin filaments, rich in cysteine, a high-sulfur amino acid, are oriented parallel or perpendicular to the growth axis). This condition leads to nails that split, flake, and crumble, becoming soft and losing elasticity. In women, the intercellular keratinocyte bridges are constitutionally weaker than in men. Old age further weakens these bridges. Environmental factors that produce progressive dehydration of the nail plate (eg, wet working conditions, minor trauma, and overaggressive manicuring) also play important roles in the development of nail brittleness. However, some investigators disagree that nail plate cohesion is related to water content.
When the amount of water in nails is reduced to less than 16%, they become brittle. Several factors are able to influence this water content, including lipids. Normal nails contain 5% lipids, which are organized in a bilayer structure, parallel to the nail surface. Lipids fill certain ampullar dilatations of the dorsal plate and intercellular spaces in the ventral plate. Low lipid content decreases the nail’s ability to retain water. A study showing a decrease in cholesterol sulfate in the nail plate with age, especially in women, suggests an important role of lipids in the development of nail brittleness in postmenopausal women.
Nail fragility manifests with several nail plate abnormalities (onychoschizia, onychorrhexis, keratin granulation, erosions, distal wedge-shaped incision) that may be associated with the same nail or be present in different nails of the same patient.
Nail plate thinning caused by proximal nail matrix damage always involves the whole nail length and is often associated with abnormalities in the superficial nail plate. In contrast, damage to the distal matrix may produce alterations in the shape of the nail plate free edge.
Treatment
Nail fragility significantly impairs daily activities and occupational abilities. Its treatment requires time and patience ( Box 1 ). Because the nail plate is a completely keratinized, dead structure, injuries cannot be repaired and each accident is added to the previous damage, rendering the nail plate more and more weak. The damaged portion is cured only when it grows out and is cut away.
- 1.
Reduce trauma and contact with water and detergents.
- 2.
Wear cotton gloves under rubber gloves during manual work.
- 3.
After any soaking, rehydrate nails with topical moisturizers.
- 4.
Keep nails short and squared.
- 5.
File nails in only one direction with a cardboard file.
- 6.
Avoid nail cosmetics; they might be potentially harmful.
- 7.
Remember that the keratin filaments are harder at a slightly acid pH.
If nail brittleness is caused by a dermatologic or a systemic condition, the first thing to do is to treat the disease to obtain an improvement of the symptom.
Oral supplementation with vitamins (especially biotin), oligoelements, and amino acids (especially cysteine) can be useful in improving nail strength.
Biotin can be useful because it may improve the synthesis of the lipid molecules that produce binding between nail plate keratinocytes. The recommended oral dose is 5 to 10 mg/d, with 2 months being the average time before clinical improvements are observed. The recommended time of treatment is 3 to 6 months, but it is not clear how long the improvement in nail strength lasts after cessation of treatment.
Iron supplementation may be effective when serum ferritin levels are less than 10 ng/mL, but there are no studies showing that iron deficiency is strictly correlated with nail fragility. Zinc deficiency is known to cause soft and fragile nails, nail plate abnormalities, and chronic paronychia. Prolonged treatment with zinc 20 mg/d seems to improve brittle nails. Silica also seems to be important in improving the resistance of the nail plate through the cross-linking of keratins.
Nail moisturizers are important in patients with brittle nails because of their occlusives, such as petrolatum or lanoline, and humectants, such as glycerin and propylene glycol. Alpha-hydroxy acids and urea may also be added to increase the water-binding capacity of the nail plate.
Also available are lacquers specifically developed to restructure nails affected by dystrophy and fragility.
A first lacquer owes its effectiveness to the presence of hydroxypropyl chitosan (HPCH), Equisetum arvense , and methylsulfonylmethane. When applied to the nails, HPCH forms a highly elastic, smooth, and almost invisible film that adheres to the nail structures, protecting them against physical injuries. HPCH is a chitosan derivative that has the advantage of being soluble in cold water without any pH correction, because the chitosan polymer backbone bears hydrophilic residues. These residues are thought to be the basis of the high affinity of HPCH with keratin. The presence of HPCH in the formulation is specifically effective in decreasing lamellar splitting.
A second lacquer made of 16% polyureaurethane, when applied to the nails, adheres tightly to the surface forming a strong but flexible waterproof barrier to environmental hazards. The active penetrates intercellular spaces and nail ridges, providing mechanical support.
Application of both lacquers is recommended once a day before bedtime.
Over-the-counter hardeners may instead paradoxically cause brittle nails if their use is prolonged. They increase the cross-link density over time, thus reducing the flexibility of the nail plate. When the nail plate is too rigid, it is also more prone to breaking and peeling. Moreover, because the hardeners are lacquers, they need to be periodically removed with a nail polish remover, which is a dehydrating agent.
Artificial nails (sculptured acrylic nails, gel nails, nail mending kits, preformed plastic nails) are commonly used to cover and protect fragile nails but they can be responsible for fragility because of the materials used and the salon procedures used to apply these materials.
Onycholysis
Onycholysis means separation of the nail plate from the underlying nail bed caused by disruption of the onychocorneal band. It generally starts at the distal free margin of the nail plate and progresses proximally. Less often, it is the other way around. It may be idiopathic, traumatic, or secondary to nail bed disorders.
Onycholysis is rarely associated with inflammation and the onycholytic area is usually smooth and whitish because of the presence of air under the detached nail plate. It may occasionally show a greenish or brown discoloration caused by colonization of the onycholytic space by chromogenic bacteria ( Pseudomonas aeruginosa ). Fungi are only secondary colonizers; treatment with systemic antifungals does not improve onycholysis, it just cures the sovrainfection.
Treatment
The cornerstone of treatment is to minimize trauma to the affected digit and avoid as much as possible water/irritant environments. Nail bed disorders should always be ruled out first. Then:
- 1.
Clip away the onycholytic nail plate and repeat this procedure every 2 weeks until the nail plate grows attached.
- 2.
The exposed nail bed should be carefully dried after each soaking.
- 3.
Application of a topical antiseptic solution (2%–4% thymol in chloroform twice a day) on the exposed nail bed may be useful to prevent infections.
- 4.
Sodium hypochlorite solution, 1 drop twice daily around the nail, removes P aeruginosa when present.
- 5.
Avoid aggressive self-cleaning under the nail plate; this promotes the spreading of the detachment.
- 6.
Do not confuse the skin debris collected under the nail plate with onychomycosis. Collect samples if necessary (evaluation of the affected area with the dermatoscope may help to rule out the presence of a fungus).
- 7.
Wear cotton gloves under rubber gloves during manual work.
- 8.
Do not wear nail cosmetics and/or artificial nails until 3 months after the onycholysis has been resolved.
It is important to promote reattachment as soon as possible, otherwise the nail bed becomes cornified, producing dermatoglyphics like the tip of the digit (disappearing nail bed). In this case the nail plate no longer adheres to the nail bed. It is generally assumed that the longer the disorder has been present, the less likely it is to resolve.
Paronychia
Paronychia is an inflammatory disorder affecting proximal and lateral nail folds. A minor trauma (mechanical or chemical) usually breaks down the cuticle, the physical barrier between the nail plate and the nail folds, allowing the infiltration of infectious organisms, allergens, or irritants that cause an inflammatory reaction that impairs nail fold keratinization, preventing the formation of a new cuticle and maintaining the condition over time. Paronychia may occur in 2 forms: acute and chronic.
Acute Paronychia
The affected digit is painful, showing erythema, swelling, and sometimes pus discharge from the proximal and/or lateral nail folds. If the infection spreads to the nail bed, it may generate enough pressure to uplift the nail plate. Beau lines and onychomadesis may occur on the nail plate as a consequence of nail matrix damage.
Chronic Paronychia
The proximal and lateral nail folds show mild erythema and swelling. Beau lines and, less frequently, onychomadesis may occur. The nail plate sometimes presents a green discoloration of its lateral margins because of P aeruginosa colonization. Secondary colonization with Candida albicans and/or bacteria is also possible, causing self-limited episodes of painful acute inflammation. Depending on the major causal factor, chronic paronychia can be classified into several types.
Irritative reaction
This is the most common form of paronychia. The lesions are generally prominent with total involvement of the proximal nail fold. The condition worsens, especially if there is an underlying eczematous condition, such as atopic dermatitis. These patients have negative patch tests and negative provocative tests. They generally improve with preventive measures.
Contact allergy
Chronic paronychia is caused by an acute contact dermatitis of the proximal nail fold and the cause of sensitization may be disclosed by patch testing.
Food hypersensitivity
Patients complain of worsening of the periungual inflammation and itching immediately after handling raw food ingredients. The diagnosis can be made with a provocative test using fresh foods on the proximal nail fold (20-minute open patch test).
Candida hypersensitivity
Patients with chronic paronychia may develop a hypersensitivity to Candida antigens. These patients usually have an immediate reaction to the intradermal skin test to Candida antigens.
True Candida paronychia
This is very uncommon, except for patients with chronic mucocutaneous candidiasis and human immunodeficiency virus infection. Proximal nail fold inflammation is usually associated with proximal onycholysis or onychomycosis caused by Candida .
Treatment
Management of any form of paronychia always requires:
- 1.
Avoidance of wet environments, chronic microtraumas, and contact with irritants or allergens (for at least 3 months after the condition is resolved).
- 2.
Wearing cotton gloves under rubber gloves during manual work.
- 3.
No aggressive/overzealous manicuring and nail cosmetics of any kind.
- 4.
Treatment of the underlying predisposing condition as well as drug interruption if these are the causes.
- 5.
Culture, radiographs, and/or biopsy, in recalcitrant cases, in order to exclude responsible disorders. They should always be ruled out when only 1 digit is involved.
Specifically, acute paronychia requires:
- 1.
Drainage of the abscess, if present, and local medications with antiseptics (2%–4% thymol in chloroform twice a day) to obtain relief of inflammation and pain.
- 2.
Sodium hypochlorite solution 1 drop twice daily around the nail to remove P aeruginosa when present.
- 3.
A topical combination of fusidic acid and betamethasone 17-valerate cream applied twice a day. This combination reduces pain first, then inflammation and swelling.
- 4.
Mupirocin cream in the morning and clobetasol cream in the evening is an alternative option.
Chronic paronychia instead requires:
- 1.
Application of a mild-potency topical steroid (methylprednisolone aceponate 0.1% cream) at bedtime.
- 2.
Tacrolimus 0.1% ointment applied twice a day as an alternative.
- 3.
A cream containing piroctone olamine and climbazole, applied twice a day for 3 months. This product combines antiinflammatory, antimicrobial, and protective activities. Patients using this cream showed disappearance of the inflammatory signs and growth of a normal nail plate, smooth and shiny. Complete cuticle regrowth was seen in greater than 50% of cases.
- 4.
Systemic steroids (methylprednisone 20 mg/kg/d) for few days in severe cases, when several digits are affected.
- 5.
Triamcinolone acetonide 2.5 mg/mL into affected nail folds (monthly injections) as an alternative in severe cases. Topical lidocaine can be applied 1 hour before the injections to reduce pain.
Systemic antifungals are often useless because chronic paronychia is not a mycotic infection. Candida is just a colonizer of the proximal nail fold that disappears when the proximal nail fold barrier is restored.
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