Lichen planus

Definition

Lichen planus is an autoimmune disorder characterised by an inflammatory condition causing itchy rashes in skin, wrists, nails, scalp,¹ inside of the mouth, lower back, ankles² and genitals.

What is an autoimmune disorder?

An autoimmune disorder is an irregular immune response where our body’s defence system kills its own healthy tissue, cells or organs.

What causes lichen planus? 

The exact cause of lichen planus is not completely understood. However, there are some possible triggers that exaggerate the condition, such as:

• Medicines that are used to treat high blood pressure, pain, heart disease and malaria
• Viral infections such as:

1. Hepatitis C
2. COVID-19 virus and its vaccine

• Lichen planus of the mouth is usually linked to an allergic response to various metals present in dental fillings, such as mercury and gold
• Stress
  Genetic factors²
  

What are the symptoms of lichen planus? 

• Skin lesions:

Commonly seen in wrists, lower back and ankles. They are commonly presented as polygonal-shaped shaped flat, itchy bumps that are shiny and purple in colour. These typical features are known as the “6 P’s of lichen planus” —> Polygonal, papules, pruritic, plaques, purple, planar (6 Ps)

• Mucosal lesions:
  • Mostly found in the mouth, but it can also be seen in the food pipe (oesophagus) and genitals
  • Appears as painful whitish lines on the inside of the mouth, cheeks and lips.
  • These white shiny lines are known as Wickham’s striae and they often erupt as sores
  • Burning sensations in the mouth, which worsen with the intake of hot and spicy foods, are some of the common complaints heard; hence, this condition is also known as burning mouth syndrome(BMS)
    
• Nail changes:
  
  • Observed changes include nail discolouration, scarring, thinning of nails and in some cases even nail loss
• Scalp involvement:
  
  • Seen as small red raised patches at the site of inflammation contributing to scarring and hair loss. Lichen planus of the scalp is known as lichen planopilaris(LPP)²
    

Diagnosis

Dermatologists often diagnose lichen planus by:

• Examining your skin, nails, scalp and mouth
  1. They check for the typical features of the lichen planus i.e; the 6 P’s
     • Polygonal in shape
     • Pruritic-itchy
     • Planar-flat topped
     • Papule-bumps
     • Purple in colour
     • Plaques-patches
• Symptoms such as itchiness, pain, or burning sensation will be checked.
• For some patients, the doctor would also suggest:
  • Allergy test
  • Skin and nail biopsy- For microscopic examination, small samples of skin and nails from your affected area will be taken
  • Hepatitis C screening test³

What treatments are available for lichen planus?

To relieve symptoms, your doctor may suggest that you follow the treatment options:

• Topical corticosteroids- Your doctor may prescribe corticosteroid ointments or creams to silence the inflammation or itchiness²
  • For stubborn lesions as seen in the scalp and nails- If there is a poor response to topical corticosteroids, then your doctor may suggest stronger medications such as intralesional steroid injections like triamcinolone. In order to suppress the itch and inflammation, these medicines will be directly injected into the scalp and nails⁴
• Antihistamines - These medicines relieve you from allergies, including itchy skin.
• Phototherapy- Phototherapy uses ultraviolet light with the help of special lamps. With carefully selected wavelength and dose, UV lights can help calm down the inflammation in the skin
• Retinoids (vitamin A derivatives) -Retinoids, such as Acitretin, is a pill or ointment that helps your body with collagen production and reduces inflammation and rashes. Retinoids should not be taken during pregnancy or 3 years before planning pregnancy

For lichen planus of the mouth

Usually, the less severe form of lichen planus goes away on its own. If you are experiencing painful ulcers, irritation, or burning sensations, your doctor would suggest a treatment plan that includes:

• Maintain good oral hygiene by regularly brushing and flossing your teeth, and get a scaling (professional cleaning of teeth) done by your dentist once in six months yearly
• Gentle brushing of teeth
• Use a soft bristle toothbrush
• Certain metals (such as mercury) present in your dental fillings can trigger lichen planus in the mouth. Your dentist may suggest you replace amalgam (containing mercury) dental fillings with a non-allergic filling to avoid a flare up of lichen planus

• Avoid drinking alcohol and eating acidic or spicy foods⁴
• Tacrolimus swish and spit treatment:- 1mg of tacrolimus capsule is dissolved in half a litre of water, swish it in your mouth for two minutes, and spit it out. For better results, do this twice daily⁵

Koebnerization (The Koebner phenomenon)

Definition

The Koebner phenomenon which is also termed as isomorphic response was first described by a German Physician named Heinrich Koebner in 1876. In Greek, “Iso” means equal and morphic means “shape”. i.e., the new lesions look similar or equal to the previous underlying skin disease.

Formation of new lesions on previously healthy skin due to a pre-existing skin condition. This is a secondary reaction caused due to trauma or injury to the skin over the existing lesions.⁶

What traumas cause Koenbner’s phenomenon?

• Self and deep scratching causing injury to the skin
• Cryotherapy (Freezing)⁷
• Insect and animal bites
• Shaving 
• Surgical incisions
• Pressure sores
• Uv radiation 
• Facial hair plucking
• Tattoos⁸

What are the common conditions showing the Koebner phenomenon?

• Psoriasis
  Lichen planus
  Warts
  Vitiligo
  Darier disease⁶

Can we prevent the Koebner phenomenon?

• The Koebner phenomenon is the activation of an existing skin disease. Therefore, managing your primary disease reduces the risk of the Koebner phenomenon. Furthermore, make sure to protect your skin from injury and sunburns.

FAQ’s

1. How fast does lichen planus spread?

Lesions appear and advance within a few weeks.

2. Is lichen planus seasonal?

            Yes, the peak incidence is seen during summer than in winters⁹

3. How long does it take for lichen planus to heal?

Skin lesions take 1-2 years to resolve while oral lesions are chronic and may take up to 5 years to resolve but eventually it can relapse.²

4. Who is more affected by lichen planus?

Middle-aged people are mostly affected by lichen planus. However, women between 30 and 60 years old are affected twice as often as people assigned male at birth.

5. Is the koebner phenomenon a disease?

The Koebner phenomenon is not a disease but rather an activation of an underlying disease.

Summary 

Lichen planus is an autoimmune condition that causes purple coloured flat-topped itchy bumps on the skin, scalp, nails and mucous membranes like the mouth, where it may be presented with Wickham's striae (white patches) and burning sensations. Triggers exaggerating lichen planus include certain viral infections such as Hepatitis C, certain medications, metal allergies in dental fillings, stress, and genetic factors. Diagnosis is made through physical examination, biopsy, allergy and Hepatitis C screening tests. Treatment usually includes corticosteroids, antihistamines, phototherapy, retinoids. The Koebner phenomenon is the rise of new lesions on previously healthy skin due to injury in people who are already affected with skin conditions such as lichen planus, psoriasis, or vitiligo. Primary ways of prevention include managing the underlying disease and protecting the skin from injury and sunburns.