Lichen simplex chronicus, also known as neurodermatitis, is a relapsing, inflammatory, pruritic and eczematous skin disorder. In 95% of cases it occurs in childhood before age 5, though an adult-onset variant is recognized. It may be associated with other atopic diseases. Symptoms vary with the age of the patients. The exact cause of the disorder is currently unknown.
The presentation of LSC is typically skin lesions making it a disease to be diagnosed more by the clinical appearance than by any lab tests. The plaques are generally well defined and well demarcated but can vary in size. The lesions of LSC usually occur over the body parts which can be easily reached to scratch. The most common sites are neck, forearms, wrist, inner side of the elbows, thighs, back of the knee, lower leg, ankle, and the vulva and anal area. Psychological factors contributevery much in the development of LSC. Patients with anxiety disorder and obsessive compulsive disorder possess an increased risk for LSC . Most prominent is the symptom of itching which is usually chronic. It could be mild or intense and the patient often complains of worsening during any period of stress. The itching also shows a trend of getting worse during periods of inactivity like bedtime . In the lesions, when carefully observed, can be distinguished three zones. The peripheral zone consists of a raised, thickened border which could be sharp and circumscribed. The middle zone consists of lenticular and hemispheric prurigo papules which is the major itch triggering part. The central zone is the area of maximum lichenification and hyperpigmentation. The lesion is smooth to touch which is specifically described as a leathery texture. It is also characterized by accentuated skin markings, scaling, scratch marks and sometimes raw bleeding areas caused by severe scratching. The lesions of LSC may also present with erosions and deep ulcerations which may be further affected by a superadded bacterial infection. The plaques of LSC appear similar to those seen in atopic dermatitis, acanthosis nigricans, lichen planus, tinea corporis, and psoriasis. However, a careful history and attention to distribution and appearance can differentiate LSC from other skin conditions.
The diagnosis of LSC can be performed primarily trhough the look and appearance of the lesions. The laboratory tests that are done serve more to exclude other skin conditions. An estimation of the Ig E levels in the blood is indicative of LSC. However, other allergic conditions can also exhibit a rise in the Ig E levels. Potassium hydroxide examination of the skin lesion scrapings of LSC will determine whether any fungal element is present. Mycotic studies and fungal cultures can be done to rule out candidiasis and tinea cruris, especially in cases of genital lesions of LSC. A patch test to detect sensitization using different allergens helps in diagnosing the triggers of allergic skin conditions . A biopsy of the site of the lesion may be necessary in certain conditions to confirm the diagnosis. Histologic examination demonstrates hyperkeratosis, acanthosis, fibrosis, and spongiosis signifying pigmentation and increased skin markings. Parakeratosis in the epidermis presents as a loss of the granular layer and its replacement with nucleated cells. The keratinocytes undergo necrosis with formation of keratinocytic amyloid in the dermis. A vertical streaking of collagen bundles is characteristic of this disorder, together with the frequent occurrence of collagen fibers directly juxtaposed to and contiguous with the lamina basalis that distinguishes LSC from other skin disorders. 
The main aim behind the treatment of LSC is to control itching in order to break the itch-scratch-itch cycle. Anti-histamines are used as the first line treatment to relieve pruritus. Diphenhydramine and hydroxyzine are the commonly used anti-histamines. Topical steroids apart from reducing itching also decrease the inflammation considerably, along with softening of the hyperkeratosis. The steroids commonly used are clobetasol and fluocinolone. It is advisable to use low potency steroids as a long term management and a high potency steroid can be used as a 3 week course in severe lichenification. Topical application of aspirin or dichloromethane has been studied to provide significant relief in pruritus, making it a practical treatment of LSC . Occlusion dressing helps in creating a physical barrier for scratching. Intralesional injections of long acting corticosteroids like triamcinalone helps in reducing thickening and pigmentation. Many case studies have proved the efficacy of botulinum toxin in the management of LSC when corticosteroids fail to or do not show results. Botulinum toxin when administered as an intradermal injection shows a therapeutic effect in blocking acetylcholine release, a mediator of pruritus, showing significant improvement in the lesions . In case of LSC, which has been secondarily infected, topical or oral antibiotics may be required to control infection. There is also a role of oral anti anxiety medicines in the treatment of LSC as stress and anxiety are definite etiological and aggravating factors. Drugs like clonazepam given throughout the day or at bedtime can help relieve symptoms.
LSC can be completely cured with an appropriate line of treatment and adequate patient education. The itching involved can be more easily controlled, while the features of lichenification take several weeks to show significant improvement . The treatment of lesions may leave behind some residual scarring or pigmented skin patches. However, the overall prognosis is very good. A relapse of LSC is common when the skin is exposed to allergens or trauma again.
Lichen Simplex Chronicus is not the primary process, but the result of repetitive rubbing and scratching of the skin caused by the sensation of itching. This itching may or may not be the result of a visible skin condition. Itching can arise plainly from irritating or tight clothing or as a result of an insect or bug bite. It is commonly seen in children that tend to scratch the skin vigorously at the site of a common occurrence as a mosquito bite. Itching can be due to a history in the family or a personal history of skin diseases like atopic eczema, psoriasis, post herpetic pruritis, asteatotic eczema, xerosis, and vascular insufficiency. These conditions cause severe itching leading to scratching which in turn increases itching. This constant process leads to lichenification. A long terms exposure to the exhaust in street traffic is known to trigger various allergic skin conditions especially in children . Other rare triggers leading to itching and scratching due to their skin irritating properties are PPD (Para-phenylenediamine) found in hair dye and lithium. Emotional disturbances like stress, anxiety, and depression tend to increase the probability of a patient to develop severe itching and scratching resulting in a cyclical process . Psychological factors have been found to have a significant role in producing skin conditions leading to LSC with certain personalities being prone to develop LSC.
Lichen Simplex Chronicus can affect people of any race, age and sex. It has been found to affect 12% of the population with some authors specifying its occurrence to be more in people with dark skin like the Asians and Africans. Though LSC affects both men and women, many data now suggest that it is more prevalent in women than men with the ratio being 2:1. The affected age is adulthood with those between 30 – 50 years of age being most susceptible to this condition.
LSC is the consequence of chronic pruritus leading to a vicious circle of itching which causes scratching that in turn worsens itching itself. Histamine has a major role to play in inflamed skin caused by various triggers like a bite or skin disorders. Several mediators and receptors, apart from histamine including the neurotrophins nerve growth factor (NGF), brain-derived neurotrophic factor, substance P, cytokines such as interleukin-31, gastrin-releasing peptide and the histamine receptor particularly H4, are the important contributors in the mechanism of itch initiation and persistence . The modulation of itch is regulated by resident cells of the skin such as keratinocytes of the basal layer, mastocytes and cells of the inflammatory infiltrate including lymphocytes and eosinophils which interact with neuronal cells. The release of neurotrophins, neuropeptides and cytokines has also been found to govern the pathways giving rise to the sensation of itching and desire to scratch. The inflammatory cell products then stimulate the central and peripheral neural tissue which marks the role of sensitization and contact dermatitis in developing LSC. As a result of all these factors and trauma to the skin, what follows is fibrosis of superficial dermis, hypertrophy of the epidermis, hyperkeratosis, and thickening of walls of small vessels appearing as exaggerated skin markings and hyperpigmentation .
Preventing scratching is the best prevention plan for LSC. Itching and scratching are the major culprits in development of LSC. Hence, the most important way to prevent thickening of the skin is by reducing pruritus. It is advisable to control itching as soon as it starts with appropriate medications. As soon as the primary symptom of itching is treated by any of the following ways, LSC can be definitely prevented from developing since the incessant trauma to the skin ceases. The part which is itchy can be bandaged or covered to prevent the skin from constant trauma. In case itching cannot be controlled, the fingernails must be kept short to prevent any deep ulcerations and infection to the skin caused by scratching with sharp long nails. If possible, the irritant to the skin causing pruritus must be identified and avoided or the use of harsh dyes, soaps, and perfumes must be avoided. It is also preferable to wear loose and smooth material clothing to stay away from any itching triggers. Stress and anxiety should be treated immediately and adequately to help the body relax and abate any neurological pathways that could worsen itching.
Lichen Simplex Chronicus (LSC) is a skin disorder arising as a result of constant rubbing or scratching of the skin. When skin is continuously irritated with any action causing friction, it eventually becomes lichenified or thickened with a dark, leathery appearance. This may occur with or without any underlying cause. It is a common condition in people with allergies of the skin which compels them to rub and scratch all the time. LSC can be symptomatically relieved with over-the-counter medicines to reduce itching or may require an appropriate medical consultation when the symptoms get worse. LSC is not a grave skin condition and may lead to a superadded bacterial infection due to trauma and bleeding which can be treated with antibiotics. A simple condition but that can some time be disturbing due to cosmetic reasons too.
Lichen Simplex Chronicus (LSC) is a skin disease characterized by the thickening, blackening and disfiguration of the skin. This disorder is localized to particular parts of the body and appears as distinct areas of raised itchy parts. These lesions usually develop on the parts of the body that are most accessible to the patient to scratch and rub. LSC develops as a result of the vicious cycle of itching leading to scratching and scratching in turn worsening itching. This constant irritation injures the layers of the skin which ultimately results in loss of the normal texture and functioning. A damage to the cells results in the change of appearance and feel of the part affected. The skin gives a leathery feel on touch with hyperpigmentation. Patches show elevated edges with increased skin markings. It has been seen that LSC mostly affects women more than men in the age group of 30 to 50 years. The factors that cause LSC are anything that trigger irritation and itching of the skin. These are allergic conditions of the skin like atopic dermatitis, insect bite, tight or rough clothing, and dyes and soaps containing certain allergens. Another very important causative and aggravating factor of LSC is stress or anxiety. People who develop LSC are known to have typical personality traits of a psychologically disturbed state. The treatment and management of LSC is aimed at reducing itching and scratching with medications like anti-histamines and local or injectable corticosteroids. The patients who do not respond to conventional therapy are also given local application of aspirin or injection of botulinum toxin with significant relief in the symptoms as well as the appearance of the part affected. The best way to prevent LSC is controlling itching as soon as it surface by means like avoiding irritants, wearing smooth textured clothes, taking cold baths with baking soda added to the water, applying ice to the affected parts, and covering the part to avoid scratching. Keeping the nails short helps in preventing trauma to the skin. Though an extremely disturbing disorder, it can be efficiently controlled and treated with adequate therapy.