Lichen Planus: Causes, Clinical Features, Diagnosis

The condition known as lichen planus affects the skin, hair, nails, mouth, and genitalia. Lichen planus frequently manifests on the skin as flat, purple, itchy pimples that grow over several weeks. Lichen planus develops lacy white patches in the mouth and vaginal mucosa, occasionally accompanied by uncomfortable ulcers. It is an Autoimmune disorder and It is mediated by T cells. It affects the Basement Membrane Zone.

Read this blog further to get a quick overview of this important topic Lichen Planus: Causes, Clinical Features, Diagnosis, Treatment, Complications for DERMATOLOGY to ace your NEET PG exam preparation.

Causes of Lichen Planus

The exact cause of this condition is unknown. In an external agent, it can be an Infection that's why we check for Hepatitis B, and C in patients or it can be a Drug. 

Some basic drugs which can cause Lichen Planus are:

• Antibacterials
• Anti-Tubercular Drug
• Antihypertensive
• Antimalarials 
• Anticonvulsants
• Heavy metals-gold, lithium
• Dental Amalgams:
• In oral Lichen Planus, rule out dental Amalgams-  If dental amalgam was placed before the development of Lichen Planus, tell the patients to get the dental amalgam removed.

Clinical Features

Below are listed a few of the clinical manifestations of lichen planus:

• Papulo squamous disorder which affects
  • Skin
  • Mucosa
  • Hair and nails. 
• It is Pruritic and it affects Flexures. 

• The characteristic lesion of Lichen Planus is 5 p's-
  • Purplish
  • Plane topped
  • Pruritic
  • Polygonal
  • Papules and Plaque. 

It affects flexures more than extensors but can be present anywhere on the body.  The common sites are flexors of the wrist or on the ankle. 

Post-inflammatory Hyperpigmentation

The Lichen Planus is hilled with hyperpigmentation, which is called post-Inflammatory Hyperpigmentation. hyperpigmented Macules are known as Hilled legion of Lichen Planus.

Koebner's Phenomenon

The occurrence of fresh skin lesions from an existing dermatosis on sites of cutaneous damage in otherwise healthy skin is known as the Koebner phenomenon. It is also referred to as the isomorphic response and the Köbner phenomenon. Lichen Planus also shows Positive Koebner's phenomenon. Papules developed along the line of trauma.

Wickham's Striae

The whitish streaks on the regions of the hand lens. This happens because of hypergranulosis (the granular layer is increased in thickness).

Oral lesions:

In the mucosa, oral lesions are present which are symptomatic. The symptoms include pain & burning on eating hot spicy food. 

On examination, we can find White reticular lacy (lacy white streaks) like patterns in the oral mucosa, especially on the mucosa.

Dental Amalgam 

In this condition, we can find a Whitish reticular lacy pattern on the mucosa. Oral Lichen Planus can affect other mucosa also such as genital or rectal mucosa.

Variants in Oral Mucosa:

• Reticular (most common), 
• Erosive
• Atrophic
• Ulcerative. 
• Ulcerative is a premalignant condition. 

Annular LP

In this condition, we can find Ring like region at a glance with central clearing. It can also be present in the other parts of the body.

Trachyonychia

In this condition, we can find rough, dry, brittle nails. Longitudinal ridging of nails is the most common finding. The nails look rough and there is dryness known as Sandblasted nails. Trachyonychia means rough, dry, brittle nails. Lichen Planus is one of the causes of Trachyonychia. 

Pterygium

It is the most specific finding. Pterygium is the wing-shaped extension of the proximal nail fold on the nail plate. It causes a tent-like appearance of the nail which is known as the tenting of the nail. 

Cicatricial / Scarring alopecia

Lichen Planus is an important cause of Scarring alopecia. In this condition, The hair follicles are destroyed. Scarring occurs with no growth of hair. This is an irreversible condition.

Also Read :

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Xerosis (Dry Skin): Causes, Symptoms, Risk Factors, Diagnosis, Treatment, Prevention and Complications

Other Types of Lichen Planus 

• Actinic Lichen Planus- it is associated with solar exposure and is seen in photo-exposed areas. 
• Hypertrophic Lichen Planus- In this Lichen Planus area is thickened and it appears Hypertrophic.
• LP Pemphigoids- it is a Combination of Lichen Planus and over that, we get pemphigoid regions. 
• Annular Lichen Planus

In Tuberculosis we can find Lichen Scrofulosorum and Lichen Amyloidosis. But these are not Lichen Planus. Lichen is something that is Purplish or has a Lichenified or lichenoid histology.

Dermatology Related Articles:

Histopathology

In Stratum Corneum- Hyperkeratosis (increased thickening) can be found.

              Hyperkeratosis

• In Stratum Granulosum- Hypergranulosis is found and this is typically focal, wedge-shaped hypergranulosis. 
• In Starting Spinosum- Acanthosis is seen.

The most important changes occur in Stratum Basale. The infiltrate targets the Stratum Basale layer and basal Cell Degeneration is seen. Keratinocyte turns into apoptotic bodies (undergoes apoptosis) which are called Civatte bodies.

Melanin (dendritic melanocytes) is also targeted. They release their melanin which falls into the dermis and leads to melanin incontinence. Melanin is engulfed by Macrophages and forms melanophages. The rete ridges are saw-toothed.

Saw-toothed rete ridges. 

Max Joseph Space- It is Space that is created between the epidermis and dermis by the infiltration of lymphocytes.  The basal cell degeneration and the infiltrate in the dermis are together referred to as Interface Dermatitis. 

Lichen Nitidus

It is usually seen in children. It is shiny, skin-colored Papules that can be present on elbows, knees, and glans. They may or may not be symptomatic. The Papules on elbows and knees are also known as Lichenoid Papules. 

On Histopathology, you see that the rete ridge is engulfing a ball of inflammation. It appears like the epidermis is engulfing this Infiltrate. So, this is called a ball in claw appearance. Treatment is when you give Topical steroids, Topical Calcineurin. 

Diagnosis Of Lichen Planus

Your doctor will likely conduct a physical examination, ask you questions about your symptoms and medical history, and diagnose your ailment. You could also require some testing. These could consist of:

Biopsy. Your healthcare professional takes a small sample of the damaged tissue for laboratory testing. The tissue is evaluated to check if it displays lichen planus-specific cell patterns.

A blood test. To check for lichen planus-related health issues, your blood may be obtained. Consider hepatitis C.

Also Read : Modes of Ventilation : Types and Uses

Treatment Of Lichen Planus

Treatments we use in Lichen Planus can be:

• Tropical:
  • Corticosteroids
  • Calcineurin Inhibitors (such as Tacrolimus, Pimecrolimus).
  • Antihistamine
  •   If oral mucosa is affected, you need to give local anesthetics.
• Intralesional: For Hypertrophic lesions, Intralesional injections of Corticosteroids are used.
• Systemic: Systemic treatment for a more severe form. Commonly used systemic agents are:
  • Oral Corticosteroid
  • Dapsone
  • HCQS
  • Azathioprine 
  • MMF (Mycophenolate Forfeited) 

All these can be used as systemic therapy for Lichen Planus.

Complications Of Lichen Planus

• Treatment for lichen planus on the vulva and in the vagina might be challenging. Scarring and excruciating pain may result. Sex can be uncomfortable if you have genital sores.
• Even after healing, the damaged skin and nails could continue to be a little darker.
• Your ability to eat could be hampered by oral sores. Oral cancer risk is increased by oral lichen planus. Lichen planus can very rarely affect the ear canal. It could result in hearing loss if left untreated.

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