Selasa, 20 November 2007

Acne Keloidalis Nuchae

Kaposi first described acne keloidalis in 1869 as dermatitis papillaris capillitii. The disease had previously been known in Hebra's clinic and is described and pictured in Hebra's atlas under the name sycosis framboesiformis. Three years after Kaposi's publication, Bazin named the condition acne keloidalis. Since then, the disease has appeared in the literature under a variety of names.

Little can be added clinically to Adamson's description of AKN in 1914. The eruption occurs on the upper posterior neck in the form of a raised transverse band at the lower margin of the hairy scalp. The band is usually dusky red in color, smooth and firm to the touch, and of keloidal consistency. It is hairless except at its upper margin, which is abrupt, broken into nodules and fringed with hair in tufts, like aigrettes, or the bunches of bristles in a brush. There may be pustules or crusted nodules here and there along the upper border. The lower margin slopes gradually to the normal skin. Usually there are no comedones or follicular pustules of acne when the patient comes under observation, and there may or may not be a history of acne of the face in youth. Often the patient complains of itching at the site of the eruption.

Pathophysiology: The exact cause of AKN is still speculative. Injury produced by short haircuts (especially when the posterior hairline is shaved with a razor, a practice common in African American men) and curved hair follicles (analogous to pseudofolliculitis of the beard in African Americans) may be the precipitating factors. Other frequently suggested etiologic possibilities are constant irritation from shirt collars, chronic low-grade bacterial infections, and an autoimmune process (AKN usually responds to systemic steroid therapy). The use of antiepileptic drugs and an increased number of mast cells in the occipital region have also been indicated as causes.

The recent findings of Sperling et al indicate that AKN is a primary form of scarring alopecia. Many of the histologic findings closely resemble those found in certain other forms of scarring alopecia. They claim that overgrowth of microorganisms does not play an important role in the pathogenesis of AKN. They also found no association between pseudofolliculitis barbae and AKN.

Herzberg et al provided another explanation based on extensive transverse microscopy, histochemistry, and electron microscopy. Herzberg et al described the following hypothetical sequence of inflammatory events that take place in AKN:

The acute inflammation, whether it begins in the sebaceous gland or elsewhere in the region of the deep infundibular or isthmus levels, is a cause or the result of a weakened follicular wall at these levels. This enables the release of hair shafts into the surrounding dermis. The "foreign" hairs incite further acute and chronic granulomatous inflammation. The localized granulomatous inflammation manifests itself clinically as a papular lesion. Fibroblasts lay down collagen and scars form in the region of the inflammation. Distortion and occlusion of the follicular lumen by fibrosis leads to hair retention in the inferior follicle and further smoldering granulomatous inflammation and scarring. The scarring and granulomatous inflammation manifest themselves clinically as keloidlike scars and plaques.

They also found that the follicular lymphocytic infiltrate contained a mixed B- and T-cell population and that the plasma cell immunoglobulins are of a polyclonal nature.

Frequency:

  • In the US: AKN is said to represent 0.45% of all dermatoses affecting black persons.

Mortality/Morbidity: AKN is a medically benign but often psychologically devastating dermatosis. Squamous cell carcinoma has developed secondary to radiation therapy in rare cases. Chronic pruritus, scarring, and drainage may occur. Without therapy, the lesions may continue to enlarge and sometimes coalesce, and new ones may appear. Scarring alopecia of the involved scalp is a common finding.

Race: AKN most often occurs in African Americans. Hispanics are the next most common group, followed by Asians and (least often) whites.

Sex: Although the early literature inferred that AKN occurred only in males, it is now known to occur in females. The male-to-female ratio is approximately 20:1.

Age: Onset usually occurs in early adulthood, but some cases do develop during adolescence. Onset prior to puberty or after age 50 years is extremely rare.

Treatment
Medical Care: After a thorough history, obtain a specimen for bacterial culture and sensitivity. A biopsy should be performed if the presentation is not typical.

Surgical Care:

Drug Name
Triamcinolone acetonide (Kenalog, Amcort) -- For inflammatory reactions responsive to steroids; decreases inflammation by suppressing migration of polymorphonuclear leukocytes and reversing capillary permeability.
Adult Dose10-40 mg/mL injected in postoperative sites q2-3wk for 4wk
Pediatric DoseNot established
ContraindicationsDocumented hypersensitivity; fungal, viral, and bacterial skin infections
InteractionsCoadministration with barbiturates, phenytoin, and rifampin decreases effects
Pregnancy C - Safety for use during pregnancy has not been established.
PrecautionsMultiple complications (eg, severe infections, hyperglycemia, edema, osteonecrosis, myopathy, peptic ulcer disease, hypokalemia, osteoporosis, euphoria, psychosis, myasthenia gravis, growth suppression) may occur; abrupt discontinuation of glucocorticoids may cause adrenal crisis
Drug Name
Prednisone (Deltasone, Meticorten, Orasone) -- May decrease inflammation by reversing increased capillary permeability and suppressing PMN activity. Used when patient has acute flare.
Adult Dose40-80 mg PO every morning
Pediatric DoseNot established
ContraindicationsDocumented hypersensitivity; viral, fungal, tubercular skin, or connective tissue infections; peptic ulcer disease; hepatic dysfunction; GI disease
InteractionsCoadministration 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
Pregnancy C - Safety for use during pregnancy has not been established.
PrecautionsAbrupt discontinuation of glucocorticoids may cause adrenal crisis; hyperglycemia, edema, osteonecrosis, myopathy, peptic ulcer disease, hypokalemia, osteoporosis, euphoria, psychosis, myasthenia gravis, growth suppression, and infections may occur with glucocorticoid use
Drug Name
Clobetasol propionate (Olux foam) or Mometasone (Elocon) -- May depress formation, release, and activity of endogenous chemical mediators of inflammation. Available as 0.025%, 0.05%, and 0.1% cream (Elocon) and as a 0.05% foam (Olux).
Adult DoseMix with equal parts of retinoic acid and apply bid sparingly to affected areas; do not use occlusive dressing
Pediatric DoseNot established
ContraindicationsDocumented hypersensitivity; fungal, viral, or tubercular skin lesions; herpes simplex or herpes zoster
InteractionsNone reported
Pregnancy C - Safety for use during pregnancy has not been established.
PrecautionsUse over large or denuded areas of the body for prolonged periods of time with an occlusive dressing or on infants may produce adverse systemic effects
Drug Name
Fluocinonide (Lidex, Fluonex) -- High-potency topical corticosteroid that inhibits cell proliferation; has immunosuppressive and anti-inflammatory properties.
Adult DoseMix with equal parts of retinoic acid and apply bid sparingly to affected areas; do not use occlusive dressing
Pediatric DoseNot established
ContraindicationsDocumented hypersensitivity; herpes simplex infection; fungal, viral, or tubercular skin lesions
InteractionsNone reported
Pregnancy C - Safety for use during pregnancy has not been established.
PrecautionsMay cause adverse systemic effects if used over large areas, denuded areas, on occlusive dressings, or during prolonged treatment periods
Drug Name
Tretinoin (Retin-A) -- Inhibits microcomedo formation and eliminates existing lesions. Makes keratinocytes in sebaceous follicles less adherent and easier to remove.
Available as 0.025%, 0.05%, and 0.1% creams. Also available as 0.01% and 0.025% gels.
Adult DoseMix with equal parts of a class 2 or 3 corticosteroid cream or gel and apply bid
Pediatric DoseNot established
ContraindicationsDocumented hypersensitivity
InteractionsToxicity increases with coadministration of benzoyl peroxide, salicylic acid, and resorcinol; avoid topical sulfur, resorcinol, salicylic acid, other keratolytics, abrasives, astringents, spices, and lime
Pregnancy C - Safety for use during pregnancy has not been established.
PrecautionsPhotosensitivity may occur with excessive sunlight exposure; caution in eczema; do not apply to mucous membranes, mouth, and angles of nose
Drug Name
Erythromycin (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 bid dosing is desired, half-total daily dose may be taken q12h. Double the dose for more severe infections.
Adult Dose250 mg PO qid taken for 10 d postoperatively to prevent infection
Pediatric DoseNot established
ContraindicationsDocumented hypersensitivity; hepatic impairment
InteractionsCoadministration may increase toxicity of theophylline, digoxin, carbamazepine, and cyclosporine; may potentiate anticoagulant effects of warfarin; coadministration with lovastatin and simvastatin increases risk of rhabdomyolysis
Pregnancy B - Usually safe but benefits must outweigh the risks.
PrecautionsCaution in liver disease; estolate formulation may cause cholestatic jaundice; GI adverse effects are common (give doses pc); discontinue use if nausea, vomiting, malaise, abdominal colic, or fever occur
Drug Name
Mupirocin (Bactroban) -- Topical antibiotic; inhibits bacterial growth by inhibiting RNA and protein synthesis.
Adult DoseApply topically bid
Pediatric DoseApply as in adults
ContraindicationsDocumented hypersensitivity
InteractionsNone reported
Pregnancy B - Usually safe but benefits must outweigh the risks.
PrecautionsProlonged use may result in the growth of nonsusceptible organisms