Published on 16/03/2015 by admin
Filed under Dermatology
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Eunice Tan and John Berth-Jones
Evidence Levels: A Double-blind study B Clinical trial ≥ 20 subjects C Clinical trial < 20 subjects D Series ≥ 5 subjects E Anecdotal case reports
Pitted keratolysis (PK) manifests as shallow punched-out circular erosions, primarily on weight-bearing, sweaty areas of the feet, and less commonly on the non-weight-bearing areas of the feet and the palms of the hands. This superficial infection of the stratum corneum is caused by Corynebacterium, Dermatophilus, Actinomyces or Kytococcus (formerly named Micrococcus). These organisms possess keratin-degrading enzymes and produce sulfur-compounds, resulting in a foul odor. Hyperhidrosis and maceration often occur concurrently.
Most patients experience little or mild irritation. Maceration, foul odor, and soreness are the main reasons for consultation. Hyperhidrosis, sweat retention, prolonged occlusion, immersion and increases in the skin pH appear to be important causes of PK. Industrial workers wearing rubber shoes or soldiers whose feet are continually occluded or wet are at high risk of developing this infection. Initial management strategies should therefore include instruction on foot hygiene and avoidance of occlusive footwear.
Treatment involves use of topical or systemic antimicrobial agents and/or reduction of the hyperhidrosis.
The topical antibiotic most commonly used by the authors is fusidic acid, which can be prescribed as 2% fusidic acid cream or ointment three to four times daily. Topical 1% clindamycin, benzoyl peroxide, 1% clindamycin with 5% benzoyl peroxide gel, 2% erythromycin, mupirocin ointment, and tetracycline and gentamicin sulfate cream have been reported to be effective. Although 1% clindamycin hydrochloride can be made up with 660 mg dissolved in 55 mL of 70% isopropyl alcohol and 5% propylene glycol, we suggest Dalacin T topical solution may be used instead. This can be applied two or three times daily. Erythromycin 2% cream or ointment has been reported to be effective if used twice daily. We suggest using 2% erythromycin gel, available as Eryacne, or 2% erythromycin solution, available as Stiemycin. Japanese dermatologists have had some success in treating PK with gentamicin sulfate cream, but this is unavailable in the UK. Mupirocin 2% ointment may be administered two to three times daily; 3% tetracycline hydrochloride ointment may be applied one to three times daily. PK has also responded to topical antifungals such as clotrimazole and miconazole; 1% clotrimazole cream or 2% miconazole cream or ointment may be applied twice daily. Topical antiseptics can be effective.
Traditionally, systemic antibiotics have been reserved for severe and resistant cases, but a 7-day course of oral erythromycin at 250 mg four times a day is usually well tolerated. The use of penicillin or sulfonamides does not seem to be effective. Antibiotic resistance has been reported with Micrococcus sedentarius to penicillin, methicillin, ampicillin, oxacillin, and erythromycin.
Topical 20% aluminum chloride hexahydrate in absolute anhydrous ethyl alcohol, available as Driclor, may reduce hyperhidrosis and odor, but the pits remain. The solution is applied at night, allowed to dry, and washed off the following day. Initially it should be used daily until the condition is brought under control, when it can be used less frequently. The use of 20% aluminum chloride hexahydrate for palmoplantar hyperhidrosis has not been as successful as its use for axillary hyperhidrosis. Topical 4% formaldehyde solution applied with gauze soaks as the patient sits or stands with their feet on the gauze in a bowl for 10 to 15 minutes once or twice daily reduces the hyperhidrosis. Alternatively, immersion of the soles of the feet in 5% formaldehyde may be utilized. Formalin ointment 40% has been used with some success but is not commercially available in the UK.
Topical 2% glutaraldehyde has been reported to have good therapeutic results in PK but sometimes the patient may require the 10% strength to reduce hyperhidrosis. Glutaraldehyde is available in the UK as Cidex (25% or 50% strength), which is used for instrument sterilization, and is somewhat hazardous to handle. Like formaldehyde, glutaraldehyde may cause contact sensitization, but it does not cross-react with formaldehyde.
Iontophoresis is frequently used in palmar and plantar hyperhidrosis and can be used in the treatment of PK. Botulinum toxin has also been used. Oral anticholinergics are perhaps excessive.
Various other agents have been tried topically but with limited success. These include 0.1% triamcinolone acetonide once or twice daily, iodochlorhydroxyquin-hydrocortisone cream (vioform-hydrocortisone) once or twice daily, flexible collodion, Whitfield ointment (6% benzoic and 3% salicylic acid ointment in a petrolatum base) twice daily, and Castellani paint. Water-repellant silicone ointment has been found not to significantly improve PK.
Wood’s light examination may reveal a coral red fluorescence, but this is not consistently helpful
Dermoscopy may reveal small black pits in a parallel pattern on the ridges of the stratum corneum
Starch iodine test may identify areas of hyperhidrosis
Shave biopsies processed with methenamine silver stain, Gram stain or periodic acid–Schiff stains are more helpful than punch biopsies
Swabs may be obtained for cultures of the organisms
No investigation is routinely required
Nordstrom KM, McGinley KJ, Cappiello L, Zechman JM, Leyden JJ. Arch Dermatol 1987; 123: 1320–5.
Micrococcus sedentarius isolated from PK lesions on the feet of eight patients was tested for antibiotic sensitivities and found to be resistant to penicillin, ampicillin, methicillin, and oxacillin. PK lesions were reproduced in one volunteer inoculated with M. sedentarius after 6 weeks of occlusion.
Kloos WE, Torrabene TG, Schleifer KH. Int J Syst Bacteriol 1974; 24: 79–101.
M. sedentarius was observed to be resistant to penicillin, methicillin, and erythromycin, which is characteristic of the genus Micrococcus.
Ertam İ, Aytimur D, Yüksel SE. Ege Tip Dergisi 2005; 44: 117–18.
A case report of a patient with plantar PK, in which Kytococcus was isolated, with complete response to 3 weeks of oral erythromycin and topical fusidic acid.
Shelley WB, Shelley ED. J Am Acad Dermatol 1982; 7: 752–7.
A case report of two patients with this triad, one of whom was treated with oral erythromycin 250 mg four times daily and a solution of 20% aluminum chloride applied nightly to the soles. Three weeks later the plantar hyperhidrosis and odor were significantly reduced, but the pits remained. The other patient declined treatment for PK.
Zaias N. J Am Acad Dermatol 1982; 7: 787–91.
The author has personal observations (non-controlled) that treatment of PK with topical clotrimazole, miconazole, erythromycin, tetracycline, clindamycin, glutaraldehyde, formaldehyde, and oral erythromycin are curative. Penicillin has not been useful.
Lee H-J, Roh K-Y, Ha S-J, Kim J-W. Br J Dermatol 1999; 140: 974–5.
A case report of PK in the palm of a patient who was suffering from postherpetic neuralgia in the same area. She had been prescribed oral erythromycin 250 mg twice daily and mupirocin ointment. Four days later the lesions had resolved.
Primary Care Dermatological Society website http://www.pcds.org.uk/patient-information-leaflets (accessed May 2012).
Patient information leaflet: 5% formaldehyde soaks for 10 minutes daily for 4 to 6 weeks for the treatment of PK.
Vazquez-Lopez F, Perez-Oliva N. Infection 1996; 24: 55.
Four patients with symptomatic PK failing to respond to conventional treatments were treated with topical mupirocin ointment, with rapid clearance of PK.
Towerser L, Azulay RD, Filho PJS, Fischman-Gompertz O, Hay RJ. J Am Acad Dermatol Supplement 2008; 58: AB88.
A case report of a patient with Kytococcus PK and associated nail dystrophy responding to systemic amoxicillin and potassium clavulanate, topical mupirocin cream for feet lesions and sulfate gentamicin solution for nail lesions.
Burkhart CG. Arch Dermatol 1980; 116: 1104.
Three patients with PK were treated with topical 1% clindamycin hydrochloride solution (660 mg dissolved in 55 mL of 70% isopropyl alcohol and 5% propylene glycol). The solution was applied to the plantar surface three times daily, and within 4 weeks there was complete resolution of the clinical lesions.
Schissel DJ, Aydelotte J, Keller R. Military Med 1999; 164: 65–7.
Case report of a soldier treated with topical clotrimazole cream twice a day, topical clindamycin solution twice a day, and topical ammonium chloride each evening. At his 2-week follow-up appointment, he reported resolution of the odor, tenderness, and interdigital pruritus, and at 8 weeks he had complete resolution.
Vlahovic TC, Dunne SP, Kemp K. Adv Skin Wound Care 2009; 22: 564–6.
The combination topical gel of clindamycin 1% with benzoyl peroxide 5% was reported to be effective in four patients, but efficacy required the concurrent use of aluminum chloride hexahydrate solution.
Kim BJ, Park KU, Kim JY, Ahn JY, Won CH, Lee JH, et al. Korean J Med Mycol 2005; 10: 144–50.
A total of 44 patients with PK were reported in this study. Seventeen received benzoyl peroxide alone, 15 received clindamycin alone, and 12 received combination benzoyl peroxide and clindamycin therapy. There was no difference in treatment efficacy between monotherapy or combination therapy. Although not significant, the clindamycin group has a slightly higher recurrence rate. Four cases recurred within 3 months and all were related to hyperhidrosis.
Stanton RL, Schwartz RA, Aly R. J Am Podiatry Assoc 1982; 72: 436–9.
Topical 2% erythromycin applied twice daily resulted in resolution of PK in both feet within 4 weeks of treatment in one case.
Shah AS, Kamino H, Prose NS. Pediatr Dermatol 1992: 9: 251–4.
Two children were reported with these lesions; treatment with topical 2% erythromycin solution twice a day was curative in both patients within 3 weeks of commencing treatment.
De Almeida Jr HL, De Castro LAS, Rocha NEM, Abrantes VL. Int J Dermatol 2000; 39: 698–709.
A case report of a patient who responded to topical erythromycin with good results.
Gordon HH. Arch Dermatol 1981; 117: 608.
Buffered glutaraldehyde 2% used with beneficial therapeutic results on PK and hyperhidrosis (uncontrolled personal observations). The author also advises that proper instructions on foot hygiene be given and sandals worn as much as possible. He reports sensitization to glutaraldehyde in some cases.
Gordon HH. Cutis 1975; 15: 54–8.
Buffered glutaraldehyde 2% applied twice daily in five patients resulted in relief of signs and symptoms except in one patient addicted to wearing boots, who continued to have hyperhidrosis. Treatment with gentamicin cream resulted in improvement.
Gordon HH. Cutis 1972; 9: 375–8.
Eight patients with a mixture of palmar and plantar hyperhidrosis were treated with varying strengths of 2%, 2.5%, 5%, and 10% aqueous glutaraldehyde with good results. Glutaraldehyde 10%, not alkalinized, was found to be rapidly effective but was associated with brown staining. Use of a 5% starting strength three times weekly minimized the tanning, and these patients were then placed on 2% or 2.5% strengths as required for maintenance treatment. None of these patients developed contact dermatitis.
Shah MK. Indian J Dermatol Venereol Leprol 2004; 70: 319–20.
Sometimes the patient with PK may require 10% glutaraldehyde to treat the hyperhidrosis. The 10% strength is likely to result in brown staining. Buffering with sodium bicarbonate may reduce the irritation but may also reduce its efficacy and stability. Glutaraldehyde 10% is prepared by mixing 15 mL of water to 10 mL of 25% glutaraldehyde. To buffer to pH 7.5, 1.65 g of sodium bicarbonate is added to 100 mL of 10% glutaraldehyde solution. The buffered solution should be used within half an hour. The author recommends thrice weekly applications for 2 weeks then once weekly as needed.
Higashi N. Jpn J Clin Dermatol 1972; 26: 321–5.
Two patients with KP were treated with topical gentamicin sulfate cream and reported to have good results.
Lamberg SI. Arch Dermatol 1969; 100: 10–11.
Report of 12 military personnel with symptomatic PK treated with various topical agents. One foot was used for treatment while the other was utilized as a control without treatment or compared with another topical agent. These included steroid creams, antibiotic creams, iodochlorhydroxyquin–hydrocortisone (vioform hydrocortisone) cream, flexible collodion, Whitfield ointment, and formalin in aquaphor (20–40%). Formalin (40%) ointment appeared to be the most effective and was used for the remainder of both asymptomatic and symptomatic patients with PK. All cases returned to full duty with the ointment after a single outpatient visit, and on re-examination the PK had resolved.
Gill KA Jr, Buckels LJ. Arch Dermatol 1968; 98: 7–11.
Water-repellent silicone ointment has no effect on PK. Lesions resolved spontaneously without treatment following removal from the moist environment.
Tamura BM, Cucé LC, Souza RL, Levites J. Dermatol Surg 2004; 30: 1510–14.
Two patients resistant to topical and systemic treatments responded completely to one course of low-dose botulinum toxin injections to the plantar aspects of the feet.
Treatment of Skin Disease Comprehensive Therapeutic Strategies 4e
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