++
SUMMARY
Potentially scarring disorder.
Varied clinical presentations.
Difficult to treat with high rate of recurrences.
++
++
TIPS FOR TREATMENT
Early treatment is recommended.
Intralesional and intramuscular triamcinolone acetonide are first-line therapies.
Retinoids and immunosuppressive agents may also be considered.
++
DON’T FORGET
Always check concomitant LP in the oral cavity.
Consider LP in other sites to establish the most appropriate treatment.
Non-responders should be in any case followed over time.
++
PITFALLS AND CAUTIONS
Consider LP even with one digit affected.
Monodactylic LP should always be confirmed histologically to rule out malignancies.
Consider also nail LP variants during clinical examination.
++
EXPERT PEARLS
Don’t hesitate and consider early treatment.
Use dermoscopy in doubtful cases to check the lunula and the nail bed.
The first prescribed successful treatment might not be effective for recurrences/relapses.
++
PATIENT EDUCATION POINTS
Do not underestimate a nail dystrophy.
Take care of your nail not to worsen dystrophic signs.
Several treatments with potential side effects may be needed to control the disease.
++
Lichen planus (LP) is an inflammatory disorder that may affect the skin, mucosae, scalp, and nails. When it is limited to the nails, it is rather uncommon (2% of all nail disorders). Instead, it is more frequent in patients with skin, scalp, or mucosal LP (10% of cases). Oral lesions are those most frequently associated with nail LP (25% of cases).1 Nail involvement may precede, coincide, or follow the development of other lesions. The awareness of these associations emphasizes the need for examining cryptic sites like mucosae or the scalp when evaluating nail changes. Nail LP may cause definitive nail destruction if not properly diagnosed and treated and it is typically difficult to treat, with a high rate of relapses and recurrences.2 Etiopathogenesis of nail LP is not well known and so are the molecular drug targets. From studies on LP of the skin and oral cavity, it seems that an over expression of IFN-gamma induced pro-inflammatory proteins on the basal keratinocytes surface, chemo-attract CD8+ T lymphocytes that target and destroy them.3–5 Mast cells and Langerhans are also involved. It has been established that mast cell degranulation induces adhesion molecule expression on endothelium, which facilitates lymphocyte homing to the tissues. Cytokines produced by lymphocytes and keratinocytes influence the local immune response and promote chronicity.6
++
Possible initial triggers are viral infections, drugs, allergy to metal in dental material,7 stress, genetic factors, and concomitant autoimmune disorders. Usually, however, nail LP is not associated with immunological disorders or other genetic disorders in adults even if a genetic susceptibility and immune imbalance have been proposed. In children, instead, the association is more frequent (30% of cases).8
+...