Lichen Nitidus (ICD-10: L44) ⚠️

Lichen Nitidus: Rare Chronic Inflammatory Skin Condition

Overview

Lichen nitidus is a rare, chronic, non-infectious dermatological condition that manifests as numerous tiny, shiny papules on the skin. The disease is typically asymptomatic, benign in nature, and usually self-limiting. Although its pathogenesis remains poorly understood, lichen nitidus is classified among inflammatory papular dermatoses and often requires only observation.

The disease can affect individuals of any age or sex but is more commonly seen in children and young adults, especially boys aged 3–10 years. In most cases, no specific treatment is needed, although topical or systemic therapy may be considered in cases involving widespread lesions or symptomatic discomfort such as itching.

Etiology and Pathogenesis

The precise causes of lichen nitidus are still unknown. Several theories suggest that it may be an immune-mediated or autoimmune skin reaction triggered by environmental, infectious, or internal factors. In some cases, it may be associated with other inflammatory skin diseases, such as atopic dermatitis, psoriasis, or vitiligo.

Lichen nitidus has also been described as a potential infectious-allergic reaction, as some patients demonstrate improvements with antibiotic therapy or have a history of focal bacterial infection. A possible genetic predisposition or association with allergic sensitivity is also under consideration due to overlaps with atopic backgrounds.

Possible triggers include:

• Mechanical skin trauma (Koebner phenomenon);
• Chronic emotional stress;
• Systemic infections or immune suppression;
• Exposure to cold or general hypothermia;
• Use of certain medications or exposure to environmental irritants.

Symptoms of Lichen Nitidus

The main symptom of lichen nitidus is the appearance of small, flesh-colored or slightly pink papules, generally 1–3 mm in diameter. These papules have a shiny, smooth surface and a flattened top. They may remain isolated or cluster together in groups, forming larger patches of densely packed lesions, but do not merge into plaques like in other dermatoses.

Additional features include:

• Papules are typically asymptomatic but may occasionally be itchy;
• Skin texture over the lesions is smooth and non-scaly;
• Surrounding skin appears normal and unaffected;
• Inflammation is minimal or absent.

Common Areas of Involvement

Lesions most commonly appear in the following locations:

• Neck and upper chest;
• Abdominal wall;
• Flexor surfaces of the arms and legs;
• Dorsal aspects of the hands and feet;
• Genital region, particularly the penile shaft in men;
• Less commonly, the palms, soles, and mucous membranes.

In widespread cases, papules may affect large portions of the trunk or limbs, potentially leading to cosmetic concern or mild discomfort.

Diagnostics

The diagnosis of lichen nitidus is primarily clinical and based on the characteristic appearance of the papules and their distribution pattern. In most cases, a dermatologist can confirm the diagnosis through visual examination and patient history.

Additional diagnostic methods may include:

• Dermatoscopy: Helps visualize the fine structure of the papules and rule out other conditions;
• KOH preparation: Used to exclude fungal infections, especially in scaly lesions;
• Skin biopsy: May be required in atypical or generalized cases. Histology typically shows a “claw clutching a ball” pattern with a granulomatous infiltrate in the dermal papilla, surrounded by epidermal hyperplasia;
• Patch or allergy testing: If there is suspicion of allergic etiology or drug reaction.

Differential Diagnosis

Several dermatoses can resemble lichen nitidus, making differential diagnosis essential in ambiguous cases:

• Psoriasis (guttate or plaque type): Usually presents with silvery scaling and a positive Auspitz sign;
• Lichen planus: Often pruritic with violaceous color and Wickham striae;
• Molluscum contagiosum: Dome-shaped papules with central umbilication, caused by poxvirus;
• Milia: Small, white, keratin-filled cysts seen mainly on the face;
• Comedones: Open or closed plugs in acne-prone areas;
• Drug eruptions: Certain medications can cause lichenoid reactions or mimic lichen nitidus.

Treatment

In most cases, lichen nitidus resolves spontaneously within several months and does not require specific treatment. However, if lesions are extensive, persistent, cosmetically concerning, or associated with pruritus, the following treatment options may be considered:

Topical treatments:

• Low- to mid-potency corticosteroids: Reduce inflammation and itching in localized lesions;
• Topical calcineurin inhibitors: Tacrolimus or pimecrolimus, especially for sensitive areas such as face or genitals;
• Emollients and moisturizers: Improve barrier function and skin comfort;

Systemic and phototherapy options (in resistant or widespread cases):

• Oral retinoids (acitretin): May be used in generalized cases;
• Phototherapy (narrowband UVB or PUVA): Can reduce lesion burden and support remission;
• Oral antihistamines: Useful if itching is a prominent symptom.

Complications

Lichen nitidus is generally considered a benign and self-limiting disease with a favorable outcome. Serious complications are rare. However, in some individuals, visible lesions may cause:

• Psychosocial distress: Especially in adolescents or adults with extensive involvement;
• Post-inflammatory pigmentation changes: Temporary darkening or lightening of affected skin;
• Residual cosmetic concerns: In long-standing or generalized variants.

Prognosis

The prognosis for lichen nitidus is excellent. In most cases, the rash resolves on its own within months to a couple of years. Generalized forms may take longer to remit, and isolated cases may persist intermittently. The condition does not increase the risk of malignancy or systemic disease.

Conclusion

Lichen nitidus is a rare, non-contagious, chronic papular dermatosis of unknown origin. Despite its benign nature and usually asymptomatic course, it may pose diagnostic and cosmetic challenges. Most patients do not require treatment, but topical or systemic therapies may be used when lesions are symptomatic or widespread.

Timely consultation with a dermatologist ensures accurate diagnosis, monitoring for atypical evolution, and the exclusion of more serious skin diseases that may mimic lichen nitidus.