Acne keloidalis nuchae =العد الجدري |
Acne keloidalis nuchae
Acne keloidalis nuchae (AKN) is a scarring form of chronic folliculitis that manifests as follicular-based papules and pustules, which eventuates in keloidlike lesions. The lesions are most pronounced on the occipital scalp and the posterior part of the neck, and they occur almost exclusively in young males of African descent.1 The term acne keloidalis nuchae is somewhat of a misnomer because the lesions do not occur as a result of acne vulgaris and are histologically not keloidal.2 Acne keloidalis nuchae was first recognized as a discrete entity in the late 1800s. Hebra was the first to describe and document this condition in 1860, under the name sycosis framboesiformis. Subsequently in 1869, Kaposi described this same condition as dermatitis papillaris capillitii.3 The term acne keloidalis was then given to this condition in 1872 by Bazin, and, since that time, this is the name most often used in the literature.2 Clinically, the lesions initially manifest as mildly pruritic follicular-based papules and pustules on the nape of the neck. Because the folliculitis is persistent, ultimately keloidlike plaques eventuate. The area is typically hairless, but broken hair shafts, tufted hairs, and ingrown hairs can sometimes be identified within and at the margins of the plaques. Over time, the plaques typically slowly expand. The lesions are disfiguring and can be painful. Abscesses and sinus tracts with purulent discharge may develop in advanced cases. Comedones are not a common feature of acne keloidalis nuchae. PathophysiologyThe exact etiology of acne keloidalis nuchae (AKN) remains obscure; however, one postulation is that chronic irritation and inward growth of coarse, curved hairs may play a role in the development of these lesions. This hypothesis is supported by the fact that lesions are exacerbated by close shaving and/or recurrent rubbing of the area by clothes or athletic gear. In a study of 453 high school, college, and professional American football players, 13.6% of African American athletes had acne keloidalis nuchae, whereas none of the white athletes had acne keloidalis nuchae.4
HistoryImportantly, note the duration of acne keloidalis nuchae (AKN), the duration of the acute flare, past therapeutic successes and failures, present medications, hair grooming techniques, and any known allergies. Regardless of symptomology, in general the lesions are cosmetically bothersome. Early papular lesions are usually asymptomatic, but pustular lesions are often pruritic and occasionally painful. Large lesions can be painful. Abscesses and sinuses may be present and may emit purulent, malodorous discharge. Hats, shirts, jackets, and sweaters can irritate the involved area. PhysicalEarly lesions manifest as firm, dome-shaped, follicular-based papules that are 2-4 mm in diameter. The papules are predominately located on the occipital region and nape of the neck. Pustules may be present, but often only excoriated papules can be identified because the lesions are often pruritic or they become traumatized when the hair is groomed. As the disease progresses, more papules and pustules appear and, over time, can coalesce to form larger plaques.
CausesSuggested etiologies include the following:
Reports have linked acne keloidalis nuchae with keratosis follicularis spinulosa decalvans, a rare X-linked disorder in which individuals have a genetic predisposition toward follicular hyperkeratosis and subsequent inflammation.12,13
Laboratory StudiesBacterial culture and sensitivity testing of acne keloidalis nuchae (AKN) pustules and draining sinuses should be considered. If pathogenic microorganisms are identified, appropriate antibiotics should be prescribed. ProceduresA biopsy may be performed if the clinical presentation is atypical and to exclude other similar conditions. Histologic FindingsThe histological findings vary depending on the timing of the biopsy. The initial infiltrate is primarily composed of neutrophils and lymphocytes that are distributed around the lower infundibulum and isthmus of the hair follicle. Subsequently, the follicle and sebaceous glands are destroyed, with liberation of the naked hair shafts into the dermis. Acute and granulomatous inflammation surrounds the free hair shafts, and, ultimately, fibrosis ensues. Scarring alopecia ensues in long-standing lesions, marked by dermal fibrosis associated with numerous plasma cells. True keloidal collagen is typically not a feature. Often, acute and chronic inflammation may be present in the same region, because new lesions often develop adjacent to chronic lesions. Sinus tracks can be identified in long-standing lesions. Intact hair follicles at the margins may exhibit polytrichia, with more than one hair shaft noted in a single follicle, but this is physiologic for the occiput.14 Individual early papules may also demonstrate ingrown hairs, and these may be seen clinically in patients without progressive scarring alopecia Treatment of acne keloidalis nuchae (AKN) is difficult, and numerous modalities have been used with varying degrees of success.
Surgical Care
MedicationThe goals of pharmacotherapy are to reduce inflammation and eliminate infection, if present. CorticosteroidsThese agents are used for their anti-inflammatory properties, but they must be used with caution because they have local and systemic side effects. Topical corticosteroids may be used alone or in combination retinoic acid. Triamcinolone (Kenalog, Amcort)For inflammatory reactions responsive to steroids; decreases inflammation by suppressing migration of PMN leukocytes and reversing capillary permeability.
AdultSmall papules: 3-5 mg/mL q2-4wk until lesions resolve or flatten PediatricNot established
Coadministration with barbiturates, phenytoin, and rifampin decreases effects
Documented hypersensitivity; fungal, viral, and bacterial skin infections
PregnancyC - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus PrecautionsHypopigmentation, steroid atrophy, delayed wound healing, rare cases of adverse systemic effects Prednisone (Deltasone, Meticorten, Orasone)May decrease inflammation by reversing increased capillary permeability and suppressing PMN activity. Used when patient has acute flare.
Adult40-80 mg PO qam PediatricNot established
Coadministration with estrogens may decrease clearance; concurrent use with digoxin may cause digitalis toxicity secondary to hypokalemia; phenobarbital, phenytoin, and rifampin may increase metabolism of glucocorticoids (consider increasing maintenance dose); monitor for hypokalemia with coadministration of diuretics
Documented hypersensitivity; viral, fungal, tubercular skin, or connective-tissue infections; peptic ulcer disease; hepatic dysfunction; GI disease
PregnancyC - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus PrecautionsIncreased infections, hyperglycemia, edema, osteonecrosis, peptic ulcer disease myopathy, peptic ulcer disease, hypokalemia, osteoporosis, euphoria, psychosis, myasthenia gravis, and growth suppression may occur; abrupt discontinuation of glucocorticoids may cause adrenal crisis Clobetasol propionate (Olux)Available as a 0.05% foam (Olux).
AdultEither used alone with twice-daily dosing or mix with equal parts of retinoic acid and apply sparingly to affected areas twice daily; do not use occlusive dressing PediatricNot established
None reported
Documented hypersensitivity; fungal, viral, or tubercular skin lesions; herpes simplex or herpes zoster
PregnancyC - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus PrecautionsUse over large or denuded areas of body for prolonged periods with an occlusive dressing or on infants may produce adverse systemic effects; complications may include steroid atrophy, steroid acne, delayed wound healing, and rare cases of adverse systemic effects if used over large areas and/or under occlusion Fluocinonide (Lidex) or Mometasone furoate (Elocon)Class 2 steroid (potent). Fluocinonide available as a 0.05% cream, ointment, and gel, and mometasone furoate available as 0.1% ointment.
AdultUse alone with twice-daily dosing or mix with equal parts retinoic acid and apply bid sparingly to affected areas; do not use occlusive dressing PediatricNot established
None reported
Documented hypersensitivity; herpes simplex infection; fungal, viral, or tubercular skin lesions
PregnancyC - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus PrecautionsComplications may include steroid atrophy, steroid acne, delayed wound healing, and rare cases of adverse systemic effects if used over large areas and/or under occlusion RetinoidsAlthough the exact mechanism of action is unknown, retinoids decrease the cohesiveness of abnormal hyperproliferative keratinocytes, modulate keratinocyte differentiation, and have anti-inflammatory properties. Isotretinoin (Accutane)Oral agent that treats serious dermatologic conditions. Synthetic 13-cis isomer of the naturally occurring tretinoin (trans -retinoic acid). Both agents are structurally related to vitamin A.
Adult0.5-1.5 mg/kg/d PO (usually 1 mg/kg/d) PediatricNot established
Toxicity may occur with vitamin A coadministration; pseudotumor cerebri or papilledema may occur when coadministered with tetracyclines; may reduce plasma levels of carbamazepine and contraceptive efficacy
Documented hypersensitivity
PregnancyX - Contraindicated; benefit does not outweigh risk PrecautionsMay decrease night vision; inflammatory bowel disease may occur; may be associated with development of hepatitis; occasional exaggerated healing response of acne lesions (excessive granulation with crusting) may occur Tretinoin topical (Retin-A)Although exact mechanism of action is unknown, retinoids decrease cohesiveness of abnormal hyperproliferative keratinocytes, modulate keratinocyte differentiation, and have anti-inflammatory properties.
AdultCan be used alone or mix with equal parts class 2 or 3 corticosteroid cream or gel and apply bid PediatricNot established
Possible neutralization with simultaneous use of benzyl peroxide, and increased irritation with concomitant use of salicylic acid, resorcinol, topical sulfur, other keratolytics, abrasives, and astringents
Documented hypersensitivity
PregnancyC - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus PrecautionsPhotosensitivity may occur with excessive sunlight exposure; caution in eczema; do not apply to mucous membranes, mouth, and angles of nose AntibioticsEmpiric antimicrobial therapy must be comprehensive and should cover all likely pathogens in the context of this clinical setting. Erythromycin base (E-Mycin, Erythrocin)Inhibits bacterial growth, possibly by blocking dissociation of peptidyl t-RNA from ribosomes, causing RNA-dependent protein synthesis to arrest. For treatment of staphylococcal and streptococcal infections. Age, weight, and severity of infection determine proper dosage in children. When twice-daily dosing is desired, half total daily dose may be taken q12h. Double the dose for more severe infections.
Adult250 mg PO qid PediatricNot established
Coadministration may increase toxicity of theophylline, digoxin, carbamazepine, and cyclosporine; may potentiate anticoagulant effects of warfarin; coadministration with lovastatin and simvastatin increases risk of rhabdomyolysis
Documented hypersensitivity; hepatic impairment
PregnancyB - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals PrecautionsCaution in liver disease; estolate formulation may cause cholestatic jaundice; adverse GI effects are common (give doses pc); discontinue use if nausea, vomiting, malaise, abdominal colic, or fever occur Mupirocin (Bactroban)Topical antibiotic; inhibits bacterial growth by inhibiting RNA and protein synthesis.
AdultApply topically bid PediatricApply as in adults
None reported
Documented hypersensitivity
PregnancyB - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals PrecautionsProlonged use may result in growth of nonsusceptible organisms Doxycycline (Vibramycin)Broad-spectrum, synthetically derived bacteriostatic antibiotic in the tetracycline class. Almost completely absorbed, concentrates in bile, and is excreted in urine and feces as a biologically active metabolite in high concentrations.
Adult200 mg PO/IV immediately and 100 mg hs, followed by 100 mg bid; alternatively, 100-200 mg PO bid Pediatric<8 years: Not recommended
Bioavailability decreases with antacids containing aluminum, calcium, magnesium, iron, or bismuth subsalicylate; can increase hypoprothrombinemic effects of anticoagulants; can decrease effects of oral contraceptives, causing breakthrough bleeding and increased risk of pregnancy
Documented hypersensitivity; severe hepatic dysfunction
PregnancyD - Fetal risk shown in humans; use only if benefits outweigh risk to fetus PrecautionsPhotosensitivity may occur with prolonged exposure to sunlight or tanning equipment; reduce dose in renal impairment; consider drug serum level determinations in prolonged therapy; tetracycline use during tooth development (last half of pregnancy through age 8 y) can cause permanent discoloration of teeth; Fanconilike syndrome may occur with outdated tetracyclines Rifampin (Rifadin, Rimactane)Inhibits RNA synthesis in bacteria by binding to beta-subunit of DNA-dependent RNA polymerase, which, in turn, blocks RNA transcription.
Adult10 mg/kg/d mg PO/IV qd; not to exceed 600 mg/d Pediatric10-20 mg/kg PO/IV; not to exceed 600 mg/d |