Lichen Simplex

The term ‘lichen’ is Latin and means a plant-like moss covering trees. Lichen simplex describes a response to the skin being repeatedly scratched or rubbed over a long period (also called lichen simplex chronicus). 

A single or multiple plaques (thickened area of skin) of rough skin is formed with increased markings and sometimes little bumps around the hair follicles. Lichen simplex can affect any age group but is most common in adults and is unusual in children.

Different skin complaints, itchy infections, and persistent scratching can lead to the development of lichen simplex. Itchy skin conditions include, for example, eczema, irritant or allergic dermatitis, and psoriasis.

Lichen simplex can also form in response to the itching of dry skin or a persistently scratched insect bite. Itching due to conditions such as fungal skin infections and varicose veins can lead to lichen simplex.

Lichen simplex is more common in people who feel anxious or stressed. Damage to the nerves, e.g., due to back injury, herpes zoster infection (shingles), or stroke can lead to lichen simplex. Sometimes, no cause can be identified.

Lichen simplex does not run in families, but some skin diseases leading to lichen simplex do, such as eczema or psoriasis.

Lichen simplex can be sore but is more often very itchy. This itch usually comes in bursts, maybe worse at times of rest and at night. The irritation then prompts scratching, which in turn aggravates the skin (called the itch-scratch cycle) and may lead to a superficial skin infection (impetigo).

Lichen simplex has increased skin markings called lichenification and can show little bumps around hair follicles. The skin may feel dry, thickened, and rough to the touch. The affected skin often looks scaly, red, and over time can become more pigmented than the surrounding skin, especially in darker skin types.

Areas more commonly affected by lichen simplex are those within easy reach of scratching, for example, the nape of the neck (lichen ‘nuchae,’ Latin for neck), the front of the legs, outer arms, and genitals. 

How is lichen simplex diagnosed? Lichen simplex is diagnosed by taking a history of the symptoms and examining the skin. Skin scrapings may be taken to exclude a fungal infection (such as ringworm). If a contact allergy is suspected, a patch-test may be given to determine an allergic reaction to anything coming in contact with the skin. If the diagnosis is not precise, a skin sample (biopsy) may need to be taken under local anesthetic for examination under a microscope.

Is lichen simplex serious? Although lichen simplex is not infectious or severe, the itching can affect sleep and quality of life. Depending on the affected area, a plaque of lichen simplex may be found unsightly or embarrassing. 

Lichen simplex will settle with the appropriate treatment but may come back when this is stopped unless an underlying cause can be found and treated. 

The itch-scratch cycle needs to be broken in lichen simplex. Any specific underlying problem, e.g., a fungal infection or contact allergy, needs to be treated. Treatment of lichen simplex may require a combination of ointments, creams, and antihistamine tablets.

Topical steroid creams.

Sometimes, steroid injections (e.g., triamcinolone) into the plaque of lichen simplex reduce both the itch and thickness. 

Tacrolimus and pimecrolimus (calcineurin inhibitors) are licensed as creams.

Coal tar creams or ointments. 

If the skin is broken or infected, an antibiotic or antiseptic cream.

Antihistamine tablets, sometimes  Antidepressants, mood stabilizers may be used.

These medications can be useful for up to a few weeks to break the itch-scratch cycle and aid sleep if taken before bedtime. Care must be taken when used during the day, as they may cause drowsiness and interfere with the ability to drive or operate machinery.

Many people with lichen simplex are helped by psychological therapy to change scratching behavior (habit reversal therapy) or reduce tension and stress.

Some people with chronic widespread lichen simplex benefit from ultraviolet light treatment, usually given in a specialist hospital department or immunosuppressive tablets such as ciclosporin or methotrexate.

Avoid anything which may irritate the area. This allergy can happen when in contact with clothing made from wool or synthetic fiber – cotton and silk are best. Nails should be kept short to avoid accidental damage to the skin. Make a conscious effort not to scratch. Whenever the skin feels itchy, apply a moisturizer instead of scratching.