What skin condition is lichen nitidus? Is this a contagious disease? What are the changes we can observe in the skin and the mechanisms underlying it? What are the various treatments for this skin condition?  Let us explore and review in this article.

Overview of lichen nitidus

Lichen nitidus is a common skin condition characterised by tiny spots or bumps on the skin surface. It is skin colored and may appear as white, yellow, or reddish brown. They usually are smooth or flat, and exhibit a shiny surface. They can occur on any surface of the body. The exact cause is not known, but according to researchers, it might be due to a triggered immune response.¹

It is most commonly seen in children and young adults, with no particular affinity to any specific race or sex. It can be seen commonly on hands, legs, abdomen, chest and penis. It is generally not symptomatic and does not spread to others. It is usually treated for patients with symptoms and cosmetic reasons.²

Signs and symptoms

 Lichen nitidus has a history of longer duration and continues to recur. Multiple shiny bumps are seen, which are skin colored and are 1-2mm in size. It does not have any symptoms, but might occasionally be associated with itching. It appears on the genitalia, chest, and abdomen and might be widespread.

 It has no affinity to any race or sex. The multiple skin bumps are typically seen in both children and young adults. There are bumps also on palms, soles, and nails. Koebner's phenomenon is a distinctive characteristic of lichen nitidus.

Additionally, the other variants of lichen nitidus are hemorrhagic, confluent, linear, perforating, Spinous follicular, Vesicular, generalised, and Actinic.

Some rare variants are purpuric lichen nitidus, which will present as red brown bumps. This is due to the rupture of blood vessels within the bumps. Actinic lichen nitidus appears as tiny, lichenoid bumps in children and adults with Fitzpatrick skin types 4 to 6. When these bumps form in a line, lichen nitidus can look like lichen spinulosus.

Causative mechanism and changes in lichen nitidus

Lichen nitidus is an inflammatory skin condition. These bumps stay for a longer duration. It has definite clinical and histopathological features, but the pathophysiological mechanism is unclear. The theory states that lichen nitidus arises from underlying defence ( immune) mechanisms or in association with immune alterations in patients.

Allergens might trigger Langerhans cells to activate cell-mediated response, which results in lymphocytic accumulation forming distinct papules, as in lichen nitidus. These papules contain many Langerhans cells (antigen-presenting cells). Also, many viruses, mycobacteria, treponema species, Streptococcus, or any other infectious agent can activate a cell-mediated response, leading to inflammatory bumps seen in lichen nitidus.

Microscopic examination of lichen nitidus

The definitive characteristic of lichen nitidus when viewed under microscopy is its well-circumscribed granulomatous infiltrate. It gives a ball a clutch appearance. During the early stage, the bumps have more lymphocytes. At a later stage,  the bumps have a group of macrophages, lymphocytes, histiocytes, and Langerhans giant cells. Parakeratotic papules are a distinctive histopathological feature of lichen nitidus when compared with lichen planus, which has orthokeratotic papules.

How is lichen nitidus diagnosed?

Lichen nitidus is diagnosed by examining the skin closely. Biopsy of the skin gives a definite diagnosis of histopathological features. It is carried out by cutting a tiny piece of the skin and looking at it through a microscope. Through dermoscopy, we can diagnose and differentiate between other skin conditions.

What are the treatment options for lichen nitidus?

Patients with lichen nitidus usually do not have symptoms. The skin bumps resolve by themselves within a few months or a year. Treatment is usually prescribed to relieve itching, discomfort, or for aesthetic reasons. 

Patients should be educated about the benign nature of lichen nitidus and how it resolves gradually. Only if symptomatic and if they have aesthetic concerns, then treatment options are considered.

Topical corticosteroids are the first-line treatment options. They play a major role in managing many dermatological conditions. The FDA approves them, and they are primarily indicated for reducing inflammation and itchiness.⁷ Patients should use these medications carefully, as they may lead to adverse local and systemic effects. The commonest adverse effect of topical steroids is skin atrophy. This occurs if we repeatedly use it in the same spot.

In cases where the patient does not respond to topical therapy, systemic corticosteroids are recommended. It is mainly used for generalised lichen nitidus or in patients with severe itching and pain.

Topical calcineurin inhibitors such as Cyclosporine, Tacrolimus, Pimecrolimus, and Vocolsporin are examples of calcineurin inhibitors. Calcineurin is a protein that functions in many cell processes for signal transmission and activation of T cells. Therefore, by blocking calcineurin, these suppress-T-cells act as immunosuppressants⁸

The topical concentration of Tacrolimus is available as an ointment with concentrations of 0.03% or 0.01% in tubes of 30g and 60g sizes. Topical calcineurin inhibitors (TCI), Tacrolimus, have greater efficacy when compared with weak topical corticosteroids, and the efficacy of Pimecrolimus was weaker compared with both tacrolimus and weak topical corticosteroids⁹

Acitretin has been shown to improve symptoms in patients with bumps on their palms and soles.² 

Narrow band ultraviolet B (NB-UVB) phototherapy and topical steroid ointment were used in patients having generalised lichen nitidus. There was marked improvement with the treatments, and the lesions were completely resolved after 18 to 20 treatments. NB-UVB phototherapy might be a good alternative therapy for generalised lichen nitidus and even a good option for children.¹⁰

PUVA-  It is also called psoralen and ultraviolet A therapy. It is a combination of plant-derived compounds, psoralens, which make the skin more sensitive to light and UV light. UV light is a type of light that comes from the sun. It's divided into three types based on its wavelength: UVC, UVB, and UVA. We use both UVA and UVB in phototherapy to treat certain skin conditions.¹¹

Generalised lichen nitidus, which recurred after undergoing treatment with topical and systemic corticosteroids, totally responded to PUVA.¹²

Systemic isotretinoin was used for a patient for cosmetic reasons. She had diffuse lesions and itching. An isotretinoin 40mg dose was given daily, and the lesions had reduced after 4 months.¹⁴ The action of retinoids is to reduce inflammation by decreasing the movement of neutrophils and eosinophils to the area beneath the superficial layer of skin. 

Astimizole, dinitrochlorobenzene, Itraconazole, Isoniazid, and cyclosporine are other options also used to treat lichen nitidus.

Health care providers should educate patients about the lesion and how they can resolve it on their own. These explanations will prevent the patients from undergoing unnecessary treatment and the risk of side effects.

FAQ’s

Where do the Langerhans cells originate from?

Langerhans cells originate from bone marrow and move into the epithelium. Its function is to recognise antigens and present them during the immune response.

What is the Koebner phenomenon?

When an injury, wound, or burn happens to people with skin disease, they get new skin lesions that resemble the primary skin disease they already have.

Which skin diseases do we typically see in the Koebner phenomenon?

It is mostly seen in psoriasis, vitiligo, and lichen planus.

What do you mean by intramatricial injections for lichen nitidus?

Intramatricial injections refer to the injection of corticosteroids directly into the nail matrix to treat nails associated with lichen nitidus.

Is Lichen nitidus a harmful skin condition?

No, it is not. The bumps seen in this condition usually resolve on their own. It is good to see the doctor if there is a lot of itchiness and it is cosmetically disturbing to you.

Summary

All in all, lichen nitidus is a common skin disease that causes skin colour bumps. It generally resolves on its own. It requires treatment only if there is consistent itching. In addition, treatment can also be given for cosmetic purposes. The patient has to be educated about these skin bumps and given treatment only if necessary. This saves the patient from the side effects of all treatments mentioned.