Lichen simplex chronicus
Also known as neurodermatitis
What is lichen simplex chronicus?
Lichen simplex chronicus is characterised by thickening of the skin due to chronic rubbing or scratching. Exaggerated skin markings termed “lichenification” are common. Lichen simplex chronicus is more common in females. It is also associated with atopic disorders (asthma, eczema, hayfever).
What causes it?
The cause of lichen simplex chronicus is not well understood but it is initiated by itching. Some people may have no underlying cause or primary skin disease. In others, there is an associated skin condition such as eczema or psoriasis. It can start from a small itchy condition such as an insect bite and continued rubbing and scratching results in lichen simplex chronicus.
The condition is thought to be due to an alteration in the nerve fibres resulting in a heightened sensitivity to the itch sensation. This results in a vicious cycle of itching and scratching which becomes difficult to break. In some people, stress or anxiety can play a role in both initiating the process and exacerbating the condition.
What does it look like?
The affected skin is thickened and leathery, occasionally with surface scaling. Deep scratch marks or scars often accompany the condition. There may be redness due to inflammation and pigmentary changes can be seen, especially in darker skin types. The skin markings are often pronounced in affected areas. There may be broken hairs or a lack of hair within affected areas due to chronic scratching.
How is it diagnosed?
The diagnosis is usually based on the clinical appearance of the condition. However, skin scrapings may be taken to exclude a fungal infection. Bacterial swabs are taken if secondary infection is suspected (yellow crusting, weeping). A skin biopsy may be needed in atypical cases.
How is it treated?
Breaking the itch scratch cycle is the key to managing the condition. To reduce itching, an anti-inflammatory such as a strong corticosteroid cream may be used.
Physically covering the affected areas with specialised bandaging is helpful in reducing subconscious scratching and helping topical treatments work more effectively.
Sedating antihistamines can help reduce sleep disturbance and subconscious scratching in sleep. Other anti-inflammatory treatments include topical calcineurin inhibitors and intralesional steroid injections. Topical menthol or tar preparations can also help reduce itching.
In extensive or recalcitrant cases, phototherapy(light treatment) or oral medications such as methotrexate, cyclosporine or oral steroids may be needed.
Any underlying skin conditions including dryness of the skin should be addressed. Using moisturisers regularly and avoiding soap is recommended. It is important to keep nails short to minimise further skin trauma.
What is the likely outcome of lichen simplex chronicus?
The condition can be persistent and is prone to recurrence. Emotional stress can lead to exacerbations.
This information has been written by Dr Yin Vun
Updated 11 November 2015