Overview

Lichen nitidus (LN) is a rare skin condition most often occurring throughout childhood and early adulthood. Previously, LN was identified as a type of lichen planus (LP), a more common inflammatory disorder of the skin, but it is now recognised as two distinct diseases. In most incidences, LN is benign with a localised grouping of small flesh-coloured bumps or papules, while LP involves a rash ranging from red-purple to brown in colour. Little is known about the mechanisms which cause this disease. However, it is typically benign with lesions usually subsiding in under a year, though treatments are available to alleviate symptoms in chronic cases.

Causes of lichen nitidus

There are two main LN variants; localised and generalised. Localised LN is a more common form of the disease characterised by visibly grouped lesions. On the other hand, generalised LN is relatively rare, it spreads throughout the body and is not restricted to one particular region or organ. 

The etiology, or cause, for both, remains unknown, although an immune link has been suggested. Histopathological analysis of LN papules has revealed the presence of lymphocytes, a type of white blood cell. Lymphocytes have important roles in immune function and their presence in LN indicates an underlying immune mechanism in the cause of disease.¹ Furthermore, there have been reports of LN occurring alongside Crohn's disease and atopic dermatitis which could support the idea that the immune system is involved in the development of LN.²

There appears to be no link between gender assigned at birth or ethnic background and LN. However, variants of LN exist which have a higher incidence in certain ethnic groups, for example, actinic LN which tends to affect patients with highly melanated skin. Actinic LN shares common features with LN but eruptions are photoinduced, caused by light, and are often visible in areas of the body that receive the most sunlight such as the hands and forearms.³

Signs and symptoms of lichen nitidus

In LN patients will experience papular eruption which are small raised cutaneous bumps known as papules, which are about the size of a pin head and measure approximately 1-2mm in diameter. These characteristic papules which are shiny, flat and flesh-coloured do usually not cause any symptoms and are asymptomatic.⁴

In the localised form of the condition lesions tend to appear on the:

• Chest
• Abdomen
• Hands 
• Arms
• Genitalia 
• Buttocks

The palms of the hands and soles of the feet are not commonly affected but this can be observed in more chronic cases and in generalised LN. Oral mucosa, that is a mucus membrane lining the inside of the mouth, can be involved in generalised LN presenting as flat lesions that have been reported as grey and yellow in colour.

Changes to the nails can be seen in certain cases and can include:⁵

• Weakening or dystrophy of the nail and thinning of the nail plate
• Longitudinal/vertical ridges
• Pigmentation

Koebner’s phenomenon is also included in the clinical presentation of LN. This is the term used to describe when new lesions or bumps from a preexisting skin condition appear in areas of skin injury while other skin remains unaffected. 

Management and treatment for lichen nitidus

Following diagnosis, the majority of patients will not require additional treatment and asymptomatic papules will diminish after a period of time, typically between 1 month to a year.⁶

In cases of chronic and generalized LN treatments can be administered and can include:

• Topical corticosteroid
• Topical emollients
• Oral antihistamine 
• Topical calcineurin inhibitor
• For actinic LN avoiding exposure to sunlight is recommended
• Intramatricial injections of triamcinolone acetonide
• UV therapy particularly NB-UVB (narrowband ultraviolet B) and PUVA (psolaren and uva).

Diagnosis

If you suspect LN please be reassured that in most cases the papules are self-resolving and will heal with time. Occasionally they can cause some irritation to the patient and may be of cosmetic concern if this is the case it is recommended you speak to your GP or nurse for a consultation. Seeking medical attention is also encouraged when LN is persistent as this can indicate the generalised variant, which is a slightly more serious form of the disease.

LN can be confirmed upon visual inspection of lesions. Dermatoscopy is a method of skin examination which uses a handheld magnifier, a dermatoscope, to allow for more efficient confirmation of skin conditions including LN. Where there is any doubt other diagnostic methods may also be used including skin biopsies⁷.

FAQs

How can I prevent lichen nitidus?

Lichen nitidus cannot be prevented.

How common is lichen nitidus?

Lichen nitidus is a relatively rare condition. 

Who is at risk of lichen nitidus?

No relationship between LN and race or gender has been established, it is frequently reported in children and can occur in older adults. One variant of LN, actinic lichen nitidus does have a higher incidence in darker-skinned patients. Patients with Crohn’s disease and a number of skin conditions such as dermatitis could be more predisposed to developing LN, though there is no clearly defined relationship as the underlying mechanisms of the disease remain unknown. 

What can I expect if I have lichen nitidus?

The localised variant of LN tends to be more common and involves the distribution of small papules grouped across the forearms, upper body, buttocks and genitalia. In most cases these lesions do not produce further symptoms and will resolve between months and a year. Itching is more often experienced by patients with generalised LN where there is also an increased likelihood of changes to the nails such as weakening and ridging and of lesions in less common areas such as the mouth and palms. 

When should I see a doctor?

Lichen nitidus is mostly benign and asymptomatic, predominantly appearing as small lesions on the skin, occasionally, the patient may experience some itching. If irritation persists or the condition worsens through evident spreading it is advised that you seek medical advice. Seeing a doctor is also recommended when cosmetic changes resulting from LN begin to cause you emotional distress, as treatments prescribed accelerate healing.

Summary

Lichen nitidus involves the appearance of small bumps or papules which are usually asymptomatic and grouped together in areas of the body such as the upper body, arms, abdomen, buttocks and genitalia. LN is not associated with race or gender but children and young adults are more susceptible to developing it. Usually, you will not require medical attention and left untreated the papules will subside on their own. Positive results have been reported from UV therapy, steroids and intramatricial injections of triamcinolone acetonide in chronic and persistent cases of generalised LN.