CASE #1

A 22-year-old Asian woman complained of a pebbly plaque on the back of her neck. The patient reported that the area itched, but she rubbed it rather than scratch. The urge to rub was worst at night when she was lying in bed just before she went to sleep. During the day, while the patient was at work, she noted that the urge to rub was diminished. OTC hydrocortisone cream 1% did not help to alleviate the desire to rub or the pruritic nature of the eruption on her neck. No other areas of her body were particularly pruritic. The patient had no other medical problems.

CASE #2

A 28-year-old black man presented with a long history of flesh-colored (brown) papules coalescing to linear plaques on the nape of his neck. He had had this eruption in some form for more than 10 years. In recent years, hair had ceased to grow in the affected area, which was sometimes pruritic but never painful. The patient reported that his barber used a straight razor on the nape of his neck. There was no evidence of alopecia on any other
areas of the patient's scalp. He did not have acne or pseudofolliculitis barbae.

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CASE #1: Lichen simplex chronicus (lichen nuchae)


The diagnosis was lichen simplex chronicus (LSC), a secondary reactive process that results from scratching or rubbing and manifests clinically as increased skin markings and thickness (a visual mimic of tree bark or lichens on a stone). In the presence of a primary dermatosis, increase in skin markings and thickness is sometimes deemed secondary lichenification.

Not all patients who rub or scratch manifest with LSC. Asians appear more susceptible. It is uncertain if this proclivity of Asians is due to the manner in which they rub their skin or the manner in which their skin reacts to rubbing. Women manifest LSC more commonly than men. Lichen nuchae is a form of lichen simplex that occurs on the midposterior neck and is observed almost exclusively in women. LSC manifests most commonly in middle-aged rather than elderly patients, who have the highest incidence of xerotic skin. In one study, 12% of aging patients with pruritic skin had LSC.

LSC manifests as an individual demarcated plaque usually with increased skin markings and thickening. The skin can be darkened, i.e., hyperpigmented or brown, and may have a texture resembling a sheet of pebbles or leather. The plaques can be scaly or contain erosions. LSC can affect any body area on either side, independent of hand dominance. Common sites include the eyelids, vulva and anus, the popliteal and antecubital fossae, and the neck. Other areas include the fold behind the ears, the lower legs, the ankles, and the upper thigh. 

The morbidities associated with LSC include decreased or interrupted sleep, which affects motor and mental functioning; secondary infection; cosmetic disfigurement; scar or keloid development; and permanent skin-color alterations. LSC is not associated with increased mortality.

Like eczema, LSC is an “itch that rashes.” Early in the development of LSC, the skin is erythematous. Patients note that the pruritus is worst when they are in bed and about to go to sleep and that it is nonexistent or minimal during the daytime. Pruritus is usually intermittent; scratching provides temporary relief. Atopic patients may observe LSC in areas of previous atopic outbreaks. LSC sometimes occurs at sites of a previous irritant or allergic contact dermatitis, insect bites, or other minor skin trauma.

There is some neural basis for LSC. It seems likely that a relationship between neural tissue (both central and peripheral) and inflammatory cell products influences the perception of itch and the manifestation of lichenified skin. The nerve endings in the skin of the LSC patient are thought to manifest subtle changes related to the development of an itch-scratch-itch cycle. The more the eruption is scratched or rubbed, the more it itches, continuing the cycle.

The variants of LSC include frictional lichenoid dermatitis; pretibial pruritic papular dermatitis; unilateral, circumscribed, chronic dermatitis of the papillary-areolar areas; complex pebbly lichenification; and the giant lichenification of Pautrier (intertriginous LSC resembling a solid-tumor substantial plaque with a verrucuous cribriform surface, particularly in the genitocrural area). Some consider acne keloidalis nuchae
a variant of LSC with fibrotic keloidal scarring. Cutaneous horns have been noted to be histologic variants of LSC.

Treatment of LSC should be directed toward keeping patients from scratching. While physical barriers can aid in this regard, corticosteroids are the mainstay of treatments for LSC. It is probably best to start with class 1 ultrapotent corticosteroids, such as 0.05% halobetasol propionate, 0.1% diflucortolone valerate, or 0.05% clobetasol, for two weeks and then taper to less potent forms of treatment. Corticosteroid-impregnated tape is useful. Injections of corticosteroids into the lesion and around nerves enervating LSC can alleviate the urge to itch and thin the skin, helping to abate LSC.  

A variety of noncorticosteroid topical treatments exists. Ice is very effective for relieving pruritus; crushed ice can be applied in a bag. Other treatments include topical forms of aspirin, nonsteroidal anti-inflammatory drugs, tacrolimus (Protopic), and pimecrolimus (Elidel); 5% doxepin or capsaicin cream, and botulinum toxin injections. OTC remedies include topical camphor and menthol (Sarna original), topical pramoxine 1% (Sarna Sensitive Skin), and topical camphor, menthol, pramoxine (Sarna Ultra). Chilling these lotions seems to increase their antipruritic effect. Topical antihistamines, such as topical benzocaine, should not be used, as they commonly result in contact sensitization and allergic contact dermatitis. Antihistamines given orally are useful for their sedating rather than their antipruritic effects. Oral doxepin and clonazepam can be useful for the same reasons and to reduce anxiety. Treatment of anogenital LSC is particularly challenging, and antidepressants may be required in patients refractory to treatment or with underlying psychiatric disorders. Topical preparations containing lidocaine (e.g., LMX4 or LMX5) can be used, particularly for anogenital LSC. The role of homeopathic remedies is uncertain. Interestingly, phototherapy has not been reported as a common treatment of LSC, perhaps because studies are directed against primary causes of itch, such as atopic dermatitis, rather than secondary effects, like LSC.

This patient was prescribed topical clobetasol 0.5% cream for two weeks. Once the itching had eased, she was put on maintenance therapy with triamcinolone 0.1% ointment. This course of therapy seemed to ease the problem so that she was no longer bothered.

CASE #2: Acne keloidalis nuchae

Acne keloidalis nuchae (AKN) is a scarring eruption due to chronic inflammation of the hair follicles. AKN manifests on the nape of the neck as keloidal papules and plaques that can coalesce from juicy papules and pustules into firm plaques and nodules. The papules of AKN can be red, brown, or black with a texture that is smooth, round, or sometimes even verrucous. The papules can measure 2 mm, while the large papule-studded plaques may be as large as 2 cm. Pustules may precede the development of AKN or coexist with it. Some patients experience pain and discomfort. Because it is cosmetically disfiguring, AKN can impose a substantial psychosocial burden on patients. The condition is also known as folliculitis nuchae, folliculitis keloidis nuchae, folliculitis nuchae scleroticans, or dermatitis papillaris capillitii.

AKN was first described in 1869 by Kaposi, an Austrian dermatologist, who termed it dermatitis papillaris capillitii. Ferdinand von Hebra, author of one of the all-time most influential books on dermatology, the Atlas der Hautkrankheiten (containing some phenomenal illustrations), described AKN about the same time as Kaposi, but he dubbed it sycosis framboesiformis. In 1872, Pierre-Antoine-Ernest Bazin, a French dermatologist, named the condition acne keloidalis.

AKN occurs sporadically. It is not linked to the follicular occlusion tetrad. For the most part, AKN and pseudofolliculitis barbae occur independently of each other. AKN most commonly affects young adult males of African origin. One case report notes two Nigerian women who developed AKN on the neck.1 AKN also occurs in Hispanics, less commonly in Asians, and rarely in whites. It has not been reported in elderly patients. Neither a family history of AKN nor a positive personal or family history of keloid formation predisposes an individual to AKN.

AKN seems to have a number of proximate causes. The primary cause is thought to be shaving of the rear scalp with a straight razor. Increased frequency of shaving that involves direct application of a blade to the skin can also be associated with acne keloidalis in that area. One case of AKN in a white patient was linked to shaving an area of skin that had been severely burned.2 Other suggested causal factors are constant irritation from shirt collars or chronic low-grade bacterial infections. An increased incidence of AKN has been reported in football players and attributed to their helmets.

Use of certain medications has been linked to the development of AKN. Cyclosporine has been associated with AKN in several case reports. AKN-like lesions on the scalp have developed following use of anti-epileptic drugs.

The differential diagnosis of AKN includes tufted folliculitis of the scalp and folliculitis decalvans, but these are more reminiscent of scarring alopecia than papular keloidal processes. Acne keloidalis can be a presentation for tinea capitis. Regular keloids, folliculitis, and nevus sebaceous of Jadassohn could theoretically mimic AKN.

The classification and etiology of AKN has engendered controversy. Some authorities have argued that AKN is a form of primary scarring alopecia, while several noted clinicians have suggested that AKN is lichen simplex chronicus with fibrotic keloidal scarring. Still others have proposed that the primary basis of AKN is infectious or autoimmune. In four cases of AKN, researchers saw histologically varying stages of transepithelial elimination, suggesting that AKN might represent a transepithelial elimination disorder akin to perforating folliculitis.

Histologic examination demonstrates that AKN is not an acneiform process. In AKN, inflammation begins at the deep infundibular and isthmic levels of the hair follicle and is accompanied by absence of sebaceous glands. Acute folliculitis and perifolliculitis, with destruction of the follicular wall and the release of hair, may be noted. Central follicles can manifest predominantly acute neutrophilic or chronic lymphocytic inflammation at the upper isthmian levels and granulomatous inflammation at the deeper isthmian levels. Trapping hair fragments in the inferior portion of the follicle, with granulomatous inflammation and scarring, can result in AKN.

A variety of medical and surgical treatment modalities exist for AKN. First-line treatment is an ultrapotent topical corticosteroid. The gel form is probably most effective, as it will stick to the area and can be rubbed in immediately. Clinicians who prescribed topical clobetasol propionate foam for 8-12 weeks found that it was effective in improving AKN and had good patient acceptance.3 A topical retinoid, such as tazarotene (Tazorac), can be added and mixed with the topical steroid. Intralesional triamcinolone (Kenalog) can be injected into the area at a concentration of 3-10 mg/mL. Successful treatment of AKN with isotretinoin (e.g., Accutane) has been observed. One report noted that keratosis follicularis spinulosa decalvans in association with AKN responded to oral isotretinoin 20 mg (0.25 mg/kg) daily for 12 months.4 Silicon gel-sheet coverage has been reported effective, but I have not found this to be true in my practice. Topical clindamycin can be used to control pustules.

Surgery is usually reserved for more difficult-to-treat AKN. Excision and second-intention healing technique is sometimes helpful. AKN can be shaved down with a dermatome; when this is the approach used, I would suggest, cost considerations aside, that imiquimod (Aldara) be applied to the raw eroded skin. Both the diode and carbon dioxide lasers have been noted in case reports to be beneficial.5,6 One patient with AKN was treated with chronic tissue expansion, total resection, reconstruction of the injured area by advancing the flap of the expanded scalp, and local radiotherapy to the resultant scar. The outcome was total clearance that persisted for at least two years after treatment was stopped.7 Thus extensive sur-gery and superficial x-ray therapy can be used in recurrent and difficult-to-treat cases.

Intermittent generic clobetasol propionate gel relieved this patient's itching. Note that continuous long-term use of clobetasol should be avoided.

Dr. Scheinfeld is assistant clinical professor of dermatology at Columbia University in New York City, where he has a private practice.


References
1. Ogunbiyi A, George A. Acne keloidalis in females: case report and review of literature. J Natl Med Assoc. 2005;97:736-738.
2. Körlof B, Doebler WD, Lagerholm B. Acne keloidalis of the burned male face. Case report. Scand J Plast Reconstr Surg. 1979;13:358-360.
3. Callender VD, Young CM, Haverstock CL, et al. An open label study of clobetasol propionate 0.05% and betamethasone valerate 0.12% foams in the treatment of mild to moderate acne keloidalis. Cutis. 2005;75:317-321.
4. Goh MS, Magee J, Chong AH. Keratosis follicularis spinulosa decalvans and acne keloidalis nuchae. Australas J Dermatol. 2005;46:257-260.
5. Kantor GR, Ratz JL, Wheeland RG. Treatment of acne keloidalis nuchae with carbon dioxide laser. J Am Acad Dermatol. 1986;14(2 Pt 1):263-267.
6. Shah GK. Efficacy of diode laser for treating acne keloidalis nuchae. Indian J Dermatol Venereol Leprol. 2005;71:31-34. Accessed March 18, 2009.
7. Pestalardo CM, Cordero A Jr, Ansorena JM, et al. Acne keloidalis nuchae. Tissue expansion treatment. Dermatol Surg. 1995;21:723-724.