AUTHOR AND EDITOR INFORMATION

Section 1 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

INTRODUCTION

Section 2 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

Background

Lichen simplex chronicus (LSC) is thickening of the skin with variable scaling that arises secondary to repetitive scratching or rubbing. LSC is not a primary process. Rather, a person senses pruritus in a specific area of skin (with or without underlying pathology) and causes mechanical trauma to the point of lichenification.

A proposed variant of LSC is lichen amyloidosis. Lichen amyloidosis is described as LSC in which the keratinocytes have necrosed and formed keratinocytic-derived amyloid in the dermis. The initial insult is pruritus with resultant amyloid formation, rather than the reverse.

Pathophysiology

LSC is found on the skin in regions accessible to scratching. Pruritus provokes rubbing that produces clinical lesions, but the underlying pathophysiology is unknown. Some skin types are more prone to lichenification, such as skin that tends toward eczematous conditions (ie, atopic dermatitis, atopic diathesis). A relationship likely exists between central and peripheral neural tissue and inflammatory cell products in the perception of itch and ensuing changes in LSC. The possible interplay among primary lesions, psychic factors, and the intensity of pruritus additively influence the extent and severity of LSC.

A small study looking at LSC and the use of P-phenylenediamine (PPD)–containing hair dye showed clinically relevant improvement in symptoms after discontinuation of PPD exposure, thus providing a basis for the role of sensitization and contact dermatitis in the etiology of LSC.

Frequency

International

Exact frequency in the general population is unknown. In one study, 12% of aging patients with pruritic skin had LSC.

Mortality/Morbidity

No mortality occurs as a result of LSC. Overall, pruritus of LSC is mild to moderate, but paroxysms may occur that are relieved by moderate-to-severe rubbing and scratching. Pruritus is usually described as much worse during periods of inactivity, usually at bedtime and during the night. Touch and emotional stress also may provoke pruritus, which is relieved by moderate-to-severe rubbing and scratching.

• Lesions cause little direct morbidity; however, occasionally patients report decreased or interrupted sleep, which affects motor and mental functioning.
• LSC may become secondarily infected after excoriation.
• LSC is often visible enough to cause patients to seek treatment.

Race

No differences are reported in frequency among races, although prior authors claimed LSC was more common in Asians and African Americans. The appearance of lesions on darker skin sometimes shows follicular prominence. Secondary pigmentary alterations are also more severe in individuals with darker skin.

Sex

LSC is observed more commonly in females than in males. Lichen nuchae is a form of lichen simplex that occurs on the midposterior neck and is observed almost exclusively in women.

Age

LSC occurs mostly in mid-to-late adulthood, with highest prevalence in persons aged 30-50 years.

CLINICAL

Section 3 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

History

• Patients with LSC usually describe stable pruritic plaques on one or more areas; however, thickening of the skin occurs on any location that the patient can reach, including the following:
• • Scalp
  • Nape of neck
  • Extensor forearms and elbows
  • Vulva and scrotum
  • Upper medial thighs, knees, lower legs, and ankles

• Erythema is noted most in early lesions.
• Pruritus is described as worse when patients are still or quiet and as much less or nonexistent when patients are active.
• Pruritus is usually intermittent; the resultant scratching provides temporary relief.
• Patients may have a past medical history of a chronic skin condition or acute trauma. Patients with atopic dermatitis may have LSC in areas of former atopic outbreaks. Sites of irritant or allergic contact dermatitis, insect bites, or other past minor skin trauma sometimes demonstrate pruritus and, subsequently, LSC.
• Each palm-sized plaque may have 3 zones. A 2- to 3-cm wide peripheral zone that is barely thickened may have isolated papules. The middle zone has lenticular and hemispheric prurigo papules that may be excoriated. The central zone has the greatest thickening and pigmentary alteration.

Physical

• One or more slightly erythematous, scaly, well-demarcated, lichenified, firm, rough plaques with exaggerated skin lines are noted.
• Pigmentary changes (especially hyperpigmentation) are seen variably as in any dermatitic lesion.
• Rubbing plays a key role in lesion formation and is visualized variably by white scratch marks, erosion, and ulceration from deeper scratching.
• LSC is one of the hyperkeratotic processes from which a cutaneous horn may grow.
• Patients may scratch lesions de novo when observed. Some patients may start scratching while discussing the itch or describing the lesions.

Causes

• Atopic dermatitis results in a higher probability of developing LSC.
• Insect bites, scars (eg, traumatic, postherpetic/zoster), acne keloidalis nuchae, xerosis, venous insufficiency, and asteatotic eczema are common factors.
• Psychological factors appear to play a role in the development or exacerbation of LSC.
• • Anxiety has been reported to be more prevalent in patients with LSC.
  • Neurodermatitis is a term formerly used interchangeably with LSC, suggesting a role of anxiety or obsession as part of the pathological process of developing lesions.

• Lithium has been linked to LSC in one reported case. LSC was dependent on the administration of lithium as evidenced by the observation that the LSC remitted when the medication was discontinued and recurred when it was restarted.
• A small study looking at LSC and the use of PPD-containing hair dye showed clinically relevant improvement in symptoms after discontinuation of PPD exposure, thus providing a basis for the role of sensitization and contact dermatitis in the etiology of LSC.
• Long-term exposure to street traffic exhaust has been associated with an increase in the frequency of childhood skin diseases, including LSC.
• Some reserve the diagnosis of lichen simplex for patients who have no known predisposing skin disorder. The term secondary lichenification has been used if the eruption is initiated by a primary dermatosis.

DIFFERENTIALS

Section 4 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

WORKUP

Section 5 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

Lab Studies

• An elevated serum immunoglobulin E level occasionally supports the diagnosis of an underlying atopic diathesis.
• Perform potassium hydroxide examination and fungal cultures to exclude tinea cruris or candidiasis in patients with genital LSC.

Other Tests

• Patch testing helps exclude allergic contact dermatitis as an underlying primary dermatosis (eg, allergic contact dermatitis to nickel with secondary LSC) or as a factor in chronicity (eg, allergic contact dermatitis to topical corticosteroids used to treat LSC).

Procedures

• Frequently, skin biopsy is performed to exclude other disorders, particularly psoriasis or mycosis fungoides (cutaneous T-cell lymphoma) in elderly patients.

Histologic Findings

Histologic examination demonstrates hyperkeratosis, acanthosis, spongiosis, and patches of parakeratosis in the epidermis. Epidermal thickening of all layers is noted, with elongation of rete ridges and with pseudoepitheliomatous hyperplasia. Papillary dermal fibrosis with vertical streaking of collagen bundles is characteristic.

A characteristic finding of LSC that is noted on electron microscopy is frequent collagen fibers attached to and just above the lamina basalis.

TREATMENT

Section 6 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

Medical Care

Treatment is aimed at reducing pruritus and minimizing existing lesions because rubbing and scratching cause LSC.

• Topical steroids are the current treatment of choice because they decrease inflammation and itch while concurrently softening the hyperkeratosis. Because lesions are by nature chronic, treatment most likely is lifelong. On larger and more active lesions, a midpotency steroid may be used to treat acute inflammation. Occasionally, occlusion is used to increase potency and enhance delivery of the agent. Occlusion also provides a physical barrier to the scratching. Midpotency topical steroids are not recommended for thin skin (eg, vulva, scrotum, axilla, face). Direct long-term therapy more at daily use of low-potency nontrophogenic topical corticosteroids. High-potency topical corticosteroids may be used for 3-week courses on thicker-skinned areas.
• Oral antianxiety medications and sedation may be considered in certain patients. According to individual need, treatment can be scheduled throughout the day, at bedtime, or both. Antihistamines such as diphenhydramine (Benadryl) and hydroxyzine (Atarax) are common. Doxepin (Sinequan) and clonazepam (Klonopin) may be considered in appropriate cases.
• For infected lesions, a topical or oral antibiotic can be considered.
• Other topical medications reported to decrease pruritus include doxepin cream and capsaicin cream.
• One study suggests that topical aspirin/dichloromethane is effective in patients with LSC who have not responded to topical corticosteroids.
• In the future, both topical and systemic immunomodulators, such as topical tacrolimus, may be used in directing the changes in cellular activity that induce itching and inflammation.

Consultations

• Consultation with a dermatologist may be considered for severe cases requiring more than topical treatments or to facilitate patch testing.
• Consultation with an allergist may be considered in individuals with multisystemic atopic symptoms.
• Consultation with a psychiatrist may be necessary for patients with severe stress or compulsive scratching.

MEDICATION

Section 7 of 11  

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• Introduction
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• Differentials
• Workup
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• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

The goals of pharmacotherapy are to reduce morbidity and to prevent complications.

Drug Category: Corticosteroids

Have anti-inflammatory properties and cause profound and varied metabolic effects. Modify the body's immune response to diverse stimuli. Decrease pruritus, thin lichenification, and reduce inflammation.

Drug Name	Betamethasone (Diprolene, Betatrex)
Description	For inflammatory dermatoses responsive to steroids. Decreases inflammation by suppressing migration of polymorphonuclear leukocytes and reversing capillary permeability. Affects production of lymphokines and has inhibitory effect on Langerhans cells.
Adult Dose	Apply thin film bid for up to 2 wk
Pediatric Dose	Administer as in adults
Contraindications	Documented hypersensitivity; viral, fungal, or bacterial skin infections
Interactions	None reported
Pregnancy	C - Safety for use during pregnancy has not been established.
Precautions	May suppress adrenal function in prolonged therapy over large body surface areas; may cause atrophy/striae with prolonged use or in intertriginous (skin fold) areas; in general, not recommended for face

Drug Name	Fluocinolone (Synalar, Synalar HP, Fluonid)
Description	High-potency topical corticosteroid that inhibits cell proliferation; also is immunosuppressive, antiproliferative, and anti-inflammatory. Flurandrenolide tape (4 mcg/cm2; Cordran tape) combines this potent topical steroid with the benefits of occlusion.
Adult Dose	Apply sparingly bid for up to 2 wk
Pediatric Dose	Administer as in adults
Contraindications	Documented hypersensitivity; viral, fungal, or bacterial skin infections
Interactions	None reported
Pregnancy	C - Safety for use during pregnancy has not been established.
Precautions	May suppress adrenal function in prolonged therapy over large body surface areas; may cause atrophy/striae with prolonged use or in intertriginous (skin fold) areas; in general, not recommended for face

Drug Name	Triamcinolone (Aristocort)
Description	For inflammatory dermatosis responsive to steroids; decreases inflammation by suppressing migration of polymorphonuclear leukocytes and reversing capillary permeability.
Adult Dose	Apply thin film bid
Pediatric Dose	Administer as in adults
Contraindications	Documented hypersensitivity; fungal, viral, and bacterial skin infections
Interactions	None reported
Pregnancy	C - Safety for use during pregnancy has not been established.
Precautions	May suppress adrenal function in prolonged therapy over large body surface areas; may cause atrophy/striae with prolonged use or in intertriginous (skin fold) areas; in general, not recommended for face

Drug Name	Hydrocortisone valerate cream 0.2%
Description	An adrenocorticosteroid derivative suitable for application to skin or external mucous membranes. Has mineralocorticoid and glucocorticoid effects, resulting in anti-inflammatory activity.
Adult Dose	Apply sparingly to affected areas bid
Pediatric Dose	Apply as in adults
Contraindications	Documented hypersensitivity; viral, fungal, and bacterial skin infections
Interactions	None reported
Pregnancy	C - Safety for use during pregnancy has not been established.
Precautions	May suppress adrenal function in prolonged therapy over large body surface areas

Drug Name	Fluocinonide (Fluonex, Lidex)
Description	High-potency topical corticosteroid that inhibits cell proliferation. Has immunosuppressive and anti-inflammatory properties.
Adult Dose	Apply sparingly bid for up to 2 wk
Pediatric Dose	Administer as in adults
Contraindications	Documented hypersensitivity; viral, fungal, or bacterial skin infections
Interactions	None reported
Pregnancy	C - Safety for use during pregnancy has not been established.
Precautions	May suppress adrenal function in prolonged therapy over large body surface areas; may cause atrophy/striae with prolonged use or in intertriginous (skin fold) areas; in general, not recommended for face

Drug Category: Antipruritic agents

Oral agents may control itching by blocking effects of endogenously released histamine. Decrease sense of pruritus, sedate/calm patients, and induce sleep. Topical agents stabilize neuronal membrane and prevent the initiation and transmission of nerve impulses, thereby producing local anesthetic action.

Drug Name	Chlorpheniramine (Chlor-Trimeton)
Description	Competes with histamine or H1-receptor sites on effector cells in blood vessels and respiratory tract.
Adult Dose	4 mg PO q4-6h or 8-12 mg SR q8-12h; not to exceed 24 mg/d
Pediatric Dose	<2 years: Not recommended 2-6 years: 1 mg PO divided q4-6h; not to exceed 6 mg/d 6-12 years: 2 mg PO q4-6h or 8 mg SR PO hs; not to exceed 12 mg/d >12 years: 4 mg q4-6h SR PO hs; not to exceed 24 mg/d
Contraindications	Documented hypersensitivity; asthma attacks; narrow-angle glaucoma; symptomatic prostate hypertrophy; bladder-neck obstruction; stenosing peptic ulcer
Interactions	CNS toxicity increases with coadministration of other CNS depressants, TCAs, MAOIs, and phenothiazines
Pregnancy	B - Usually safe but benefits must outweigh the risks.
Precautions	May cause significant confusional symptoms; not for administration in premature or full-term neonates

Drug Name	Hydroxyzine (Atarax, Vistaril)
Description	Antagonizes H1 receptors in periphery. May suppress histamine activity in subcortical region of CNS.
Adult Dose	25-100 mg PO qd/qid
Pediatric Dose	0.6 mg/kg/dose PO q6h
Contraindications	Documented hypersensitivity
Interactions	CNS depression may increase with alcohol or other CNS depressants
Pregnancy	C - Safety for use during pregnancy has not been established.
Precautions	Associated with clinical exacerbations of porphyria (may not be safe for patients with porphyria); ECG abnormalities (alterations in T waves) may occur; may cause drowsiness

Drug Name	Clonazepam (Klonopin)
Description	For anxiety associated with pruritus. Binds receptors at several sites within the CNS, including the limbic system and reticular formation. Effects may be mediated through GABA receptor system.
Adult Dose	0.25-0.75 mg PO bid
Pediatric Dose	Not recommended
Contraindications	Documented hypersensitivity; severe liver disease; acute narrow-angle glaucoma
Interactions	Phenytoin and barbiturates may reduce effects; coadministration of CNS depressants increase toxicity
Pregnancy	D - Unsafe in pregnancy
Precautions	Caution in chronic respiratory disease or impaired renal function; withdrawal symptoms can result from abrupt discontinuation

Drug Name	Pramoxine (Itch-X)
Description	Blocks nerve conduction and impulses by inhibiting depolarization of neurons. Hypoallergenic topical anesthetic. Contains 0.5% menthol and 0.5% camphor, which are nonstaining agents that provide a subjective cooling effect to the skin and are much preferred to rubbing or scratching the skin.
Adult Dose	Apply to affected area q3-4h
Pediatric Dose	Not established
Contraindications	Documented hypersensitivity; do not apply over large areas; avoid contact with eyes and nose
Interactions	None reported
Pregnancy	C - Safety for use during pregnancy has not been established.
Precautions	Caution in patients with trauma in area to be treated

Drug Name	Doxepin (Sinequan, Zonalon)
Description	Inhibits histamine and acetylcholine activity. Widespread use produces sedation, as does its use in areas of high percutaneous absorption (eg, genitals). Many individuals develop allergy to topical doxepin.
Adult Dose	PO: 25-150 mg qhs Topical: Apply to affected area bid/qid
Pediatric Dose	Not recommended
Contraindications	Documented hypersensitivity; urinary retention; acute recovery phase following MI; glaucoma
Interactions	Decreases antihypertensive effects of clonidine but increases effects of sympathomimetics and benzodiazepines; effects of desipramine increase with phenytoin, carbamazepine, and barbiturates
Pregnancy	C - Safety for use during pregnancy has not been established.
Precautions	Caution in cardiovascular disease, conduction disturbances, seizure disorders, urinary retention, hyperthyroidism, and patients receiving thyroid replacement; topical preparation may be associated with drowsiness; oral medicine may cause drowsiness lasting until morning, with difficulty arising, even in low doses and particularly in elderly persons

FOLLOW-UP

Section 8 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

Further Outpatient Care

• Periodically examine patients with LSC in an outpatient dermatology clinic to evaluate lesions for changes. Perform follow-up examinations more frequently in patients being treated with potent class I topical corticosteroids or oral agents.

Deterrence/Prevention

• Direct patients to stop scratching. LSC is worsened or improved depending on the patient's ability to stop scratching.
• Extremes of temperature and/or humidity, psychic stress, and exposure of previously affected or predisposed areas to cutaneous irritants and allergens provoke relapse.
• Discussing individual ways to change habitual scratching is helpful.

Prognosis

• Lesions may clear completely.
• Pruritus may resolve, but some mild scarring and pigmentary changes remain after successful treatment.
• Relapse is more likely in periods of psychic stress or if previously affected skin is stressed by extremes of heat or humidity or by skin irritants or allergens.
• In patients who do not comply with the treatment regimen and scratching cessation, lesions will not improve.

Patient Education

• Direct patients to stop scratching. LSC is worsened or improved depending on the patient's ability to stop scratching.
• Discussing individual ways to change habitual scratching is helpful.

MISCELLANEOUS

Section 9 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

Medical/Legal Pitfalls

• LSC may complicate occupational irritant contact dermatitis and allergic contact dermatitis.
• LSC may interfere with normal wound healing following surgery in an affected area.

MULTIMEDIA

Section 10 of 11  

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
• Treatment
• Medication
• Follow-up
• Miscellaneous
• Multimedia
• References

Media file 1:  Plaque of lichen simplex chronicus demonstrating accentuated skin markings. Courtesy of San Antonio Uniformed Services Health Education Consortium Dermatology Program.
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Media type:  Photo

Media file 2:  Area of lichen simplex chronicus originally believed to be chronic contact dermatitis. The true nature was revealed when the patient admitted to rubbing this area while watching television. Courtesy of San Antonio Uniformed Services Health Education Consortium Dermatology Program.
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Media type:  Photo

REFERENCES

Section 11 of 11

• Authors and Editors
• Introduction
• Clinical
• Differentials
• Workup
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• Follow-up
• Miscellaneous
• Multimedia
• References

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Article Last Updated: May 30, 2006