What Is Lichen Spinulosus

Even though Lichen Spinolosus (LS) is often described as a rare skin condition, it affects children, adolescents, and young adults frequently. Lichen Spinolosus presents reddish patches distributed symmetrically on the elbow, shoulders, stomach, and buttocks. The patches are similar to the size of a crayon tip and usually feel like running your palms on a nutmeg grater. 

Pronounced as “LIKE-en spine-you-LOH-sis”, Lichen Spinolosus is a benign skin condition that develops in the hair follicles and causes spiny bumps.¹ This condition can be resolved on its own when managed properly. However, healthcare providers can help control the symptoms with medicated creams. 

Overview

Lichen Spinolosus was first described by Crocker and was published in 1883. Until 1990, when Friedman presented data on 35 patients with lichen spinulosus, few other reports of a similar nature had been published. A patch has been compared to the sensation of running your fingers over a nutmeg grater when it is gently rubbed with the fingers.² Although the lesions do not hurt, some patients may experience pruritus or itching. The cause is not known. 

Lichen Spinolosus typically starts abruptly and is not accompanied by other symptoms or signs. The follicular papules are tiny, rough bumps that first appear in round or oval patches. Over a few days, they quickly spread to cover large areas of skin.

Characteristics of Lichen Spinulosus can include:

• Patches and plaques of follicular papules that develop symmetrically at intervals on the neck, buttocks, thighs, abdomen, knees, and extensor surfaces of the arms. They can range in size from 2 to 5 cm.
• A horny spine that is pointed or hair-like and extends about 1mm around the tip of each follicular papule has a diameter of 1-3 mm.

Causes of lichen spinulosus

Lichen spinulosus has no known cause or remains unidentified. It appears to be an abnormal follicle reaction pattern to various triggers. Some people associate Lichen spinolosus with malnutrition, specifically a lack of vitamin A. Others believe it develops as a result of toxic exposure. Lichen spinolosus may be aggravated by underlying conditions such as Crohn's disease, HIV infection, or alcoholism.³ Lichen spinulosus is not dangerous and is not linked to any other organ system abnormalities. In most cases, it is only a cosmetic issue.

According to some researchers, Lichen Spinulosus is a subtype of keratosis pilaris, a common skin condition characterised by small bumps on the arms and legs. Among the explanations proposed for the cause are:

• The body's immune response to infection.
• Genetic influences.
• Atopic skin disorders, such as asthma, atopic dermatitis, or allergic rhinitis, are present.

Signs and symptoms of lichen spinulosus

Even though no systemic signs and symptoms are noted for LS, the following symptoms can be associated with LS:

• Sudden appearance of tiny benign lesions resembling a patch of spiny papules (each about 1 to 3 mm in size).
• A small, discoloured, raised skin bump (also known as a papule) with well-defined borders.
• Round or oval skin patches that can range in size from 2 to 6 cm and are usually symmetrical (appearing on both the right and left sides of the body).
• A single or multiple skin patches; after onset, they may quickly spread to other areas of skin over the next few days.
• The skin has the texture of fine sandpaper (nutmeg grater).
• The lesions are occasionally itchy, but pain is uncommon.
• The lesions are usually found on the neck, abdomen, buttocks, thighs, knees, and arms, but they can appear anywhere.

Management and treatment for lichen spinulosus

There is no specific treatment for Lichen spinolosus as it can resolve spontaneously on its own in most cases.⁴ However, its occurrence can be managed by;

·   The use of non-soapy cleansers.

• Applying medicated moisturising cream twice daily. Medicated creams should contain Salicylic acid, urea, and alpha hydroxy acids.
• Use of a pumice stone or an exfoliating sponge in the shower or bath.
• Applying topical retinoids on prescription. Redness and peeling of the treated areas can be expected during the first few weeks of treatment. Topical retinoids should not be used during pregnancy.
• In some cases, laser-assisted hair removal may be beneficial.

Even though it has been stated that LS does not have a known cure, some medications can be used to reduce its clinical manifestations. It has been reported that combining tretinoin gel at bedtime with hydroactive adhesives the next morning is effective.⁵ The use of topical tacalcitol cream was reported to be effective in two children with an atypical presentation of submental lichen spinulosus. There have been reports of successful treatment with topical adapalene.

Diagnosis

Diagnosis for LS is mostly made by clinical examination. Currently, there are no tests available for the diagnosis of LS. However, the histology of Keratosis pilaris is similar to LS.

Clinical findings for the diagnosis of lichen spinolosus:

1. Physical Observation
   • Patches are evenly distributed on the surface of the neck, stomach, abdomen, thighs, knees, and elbow. LS predominantly affects the elbow, ankles, and neck.
   • Multiple papules, which range in size from 2 to 5 cm, are present within the patches and plaques.
   • The papules range in size from 1-3 mm in diameter and have a central, hard, spiky projection.
2. Differential Diagnosis
   • Phrynoderma is caused by a variety of nutritional deficiencies, including Vitamin A and Vitamin B-complex. It is unusual in developed countries. Phrynoderma is distinguished by red-brown follicular papules with a central keratotic spinous plug.
   • Multiple-minute digitate hyperkeratosis (also known as spiny hyperkeratosis) is a very rare non-follicular digitate keratosis that affects the trunk and limbs. Lesions are thin, white-yellow, spiny keratotic projections that are usually very numerous.⁶ Flat-topped, dome-shaped, or crateriform papules are occasionally seen.

FAQs

How can I prevent lichen spinulosus?

Currently, there are no ways to prevent LS but there are things you can do to stop LS from aggravating;

• Avoid excessive tanning of the skin.
• The use of home humidifiers to reduce indoor air.
• Avoid excessive shaving or skin tanning.
• Moisturize your skin regularly.
• Reduce alcohol intake. 

How common is lichen spinulosus?

LS is common in children, adolescents, and young adults.  Occurrence in adults and the elderly is rare.

Who is at risk of lichen spinulosus?

Children and adolescents are at risk of LS. However, family history could be a predisposing factor to LS. Also, people with HIV infection and alcoholics are at risk of LS. 

What can I expect if I have lichen spinulosus?

Expect small tiny bumps around your arms, neck, and elbows that give the sensation of rubbing your palm against a nutmeg grater. You can expect a rough reddish patch that is similar to sandpaper. 

What part of the body does lichen spinulosus appear?

LS is symmetrically distributed on the elbows, necks, ankles, stomach, laps, and buttocks.

When should I see a doctor?

LS is symmetrically distributed on the elbows, necks, ankles, stomach, laps, and buttocks. If you suspect that you have LS, it is important to see a dermatologist to provide you with an accurate diagnosis, treatment and further guidance on this condition.

Summary

Spontaneously appearing bumps on your elbows, necks, or buttocks are characteristic of Lichen spinulosus. Lichen spinulosus is a skin condition that causes small spiny bumps to form in the hair follicles. The condition usually resolves on its own, but your healthcare provider may prescribe medicated creams to alleviate your symptoms. They may also suggest changes to your skincare routine to help control skin symptoms until the condition is resolved.