DR [page 14] [Dermatology Reports 2012; 4:e4] Plantar pitted keratolysis: a study from non-risk groups Asli Feride Kaptanoglu,1 Ozlem Yuksel,2 Selcuk Ozyurt3 1Near East University, Lefkosa-North Cyprus, Turkey; 2Bayindir Hospital Kavaklidere, Ankara, Turkey; 3İzmir Ataturk Research and Education Hospital, İzmir,Turkey Abstract Pitted keratolysis is an acquired, superficial bacterial infection of the skin which is charac- terized by typical malodor and pits in the hyperkeratotic areas of the soles. It is more common in barefooted people in tropical areas, or those who have to wear occlusive shoes, such as soldiers, sailors and athletes. In this study, we evaluated 41 patients who had been diagnosed with plantar pitted keratolysis. The patients were of high socioeconomic status, were office-workers, and most had a university degree. Malodor and plantar hyperhydrosis were the most frequently reported symptoms. The weight-bearing metatarsal parts of the feet were those most affected. Almost half the women in the study gave a history of regular pedicure and foot care in a spa salon. Mean treatment duration was 19 days. All patients were informed about the etiology of the dis- ease, predisposing factors and preventive methods. Recurrences were observed in only 17% of patients during the one year follow-up period. This study emphasizes that even mal- odorous feet among non-risk city dwellers may be a sign of plantar pitted keratolysis. A study of the real incidence of the disease in a large population-based series is needed. Introduction Pitted keratolysis is an acquired, superficial bacterial infection of the skin. The characteris- tic features of the diseaseare multiple crateri- form pits (usually in the weight-bearing areas of the soles), maceration (mostly because of hyperhydrosis), a typical unpleasant smell, and sliminess of the feet. Pitted keratolysis has a worldwide distribution, but the disease is more common among barefooted people living in tropical regions. No race or sex predilection has been reported.1-3 In this study, we docu- mented clinical and demographic data of 41 plantar-pitted keratolysis patients who were admitted to a private hospital in Ankara, Turkey. Materials and Methods The study included all patients diagnosed with plantar-pitted keratolysis in a 2-year peri- od among the patients of the dermatology department of a private hospital in Ankara. An unproblematic clinical diagnosis of pitted ker- atolysis was made in almost all of the 41 patients with the help of the unique malodor of the disease. In 11 of the patients, Gram’s stain- ing was performed to show the rod like organ- isms confirming the diagnosis of pitted kera- tolysis. However, mycotic investigations and wood light examination were carried out in every patient to exclude tinea pedis and ery- thrasma. In some suspected patients, bacterio- logical cultures or histopathological examina- tions were carried out to exclude other bacteri- ological infections and some keratodermas. Patients with a diagnosis other than pitted ker- atolysis were excluded from the study, but 4 of the patients who concomitantly had both tinea pedis and pitted keratolysis were included. Patients were investigated with a special emphasis on the triggering factors and the results were recorded. Results Of the 41 pitted keratolysis patients includ- ed in this study, 24 were male (58.6%) and 17 were female (41.4%). Patients were between 18-56 years of age (mean 38.95 years). Most of the patients were office workers of a high socioeconomic status and had a university degree (n=24, 58.6%). Thirteen patients (31.7%) had a high school degree and reported prolonged use of occlusive footwear for work. Three patients were students (7.3%) and one was not educated (2.4%). Patients mostly complained about malodor (n=41, 100%), wet feet (n=27, 66%), sliminess of the feet (n=11, 26.8%), pain and burning sensation in the feet (n=11, 26.8%) and pruri- tus (n=1, 2.4%). None of the patients reported a seasonal change in their condition. None of the patients reported involvement of the palms of their hands. Weight-bearing metatarsal regions of the feet were most commonly involved areas (n=39, 95.1%). Physical examination mostly revealed mal- odor (100%) and hyperkeratosis (58.6%) of the soles. Maceration due to hyperhydrosis was found in 31.7% of patients, whereas fissures and erythema were seen in 14.6% and 2.4% of cases, respectively. Four of the patients had concomitant tinea pedis (9.7%). Plantar warts and corns were observed in 7.3% and 2.4% of cases, respective- ly. No corynebacterial triad (pitted keratolysis, erythrasma and trichomycosis) was seen in any of the patients in the present study. As there is no system for scoring the severi- ty of plantar pitted keratolysis, treatment was planned according to the clinical appearence of lesions, depending on the anatomic extension of lesions, the hyperkeratosis and depth of the pits. Only topical treatment with 4% erythro- mycin gel was applied in 9 patients (21.9%) who had malodor and slight pits. Patients (n=32, 78.1%) with more severe clinical appearance (malodor, hyperkeratosis deep pit- ted lesions and maceration) needed both sys- temic and topical treatment. Roxytromycine 300 mg/day was used as a systemic antibiotic. Patients (n=19, 46.4%) who had malodor, hyperkeratosis and deeper pitted lesions were treated with 10% salicylic acid, including creams in addition to erythromycine gel. In patients with severe maceration, 0.01% KMNO4 solution was also used for its astrin- gent and drying properties (Table 1). Patients were controlled weekly and topical treatments were continued until symptoms had completely disappeared. All patients reported strict adher- ence to treatment and kept their checkup appointments. Treatment lasted between one and eight weeks (mean 19 days). During the treatment period, patients used cotton socks and followed suggestions for changes in their daily habits. They did not wear the same shoes for two consecutive days. During the 1-year follow up, recurrence was observed in 7 (17%) patients. Time to recur- rence was 4-12 months. The common feature of these patients was the highly hyperkeratotic tissue of the sole; one was in severe depres- sion and one was deeply immunosupressed. Discussion Pitted keratolysis is a skin disorder charac- Dermatology Reports 2012; volume 4:e4 Correspondence: Asli Feride Kaptanoglu, Near East University, Ankara, Turkey. E-mail: dr.aslikaptanoglu@gmail.com Key words: plantar pitted keratolysis; foot odour; risk groups. Received for publication: 25 July 2011. Revision received: 21 November 2011. Accepted for publication: 1 December 2011. This work is licensed under a Creative Commons Attribution NonCommercial 3.0 License (CC BY- NC 3.0). ©Copyright A.F. Kaptanoglu et al., 2012 Licensee PAGEPress srl, Italy Dermatology Reports 2012; 4:e4 doi:10.4081/dr.2012.e4 No n- co mm er cia l u se on ly [Dermatology Reports 2012; 4:e4] [page 15] terized by crateriform pits that primarily affect the pressure-bearing parts of the plantar sur- faces of the feet and occasionally the palms of the hands. The manifestations are due to a superficial cutaneous bacterial infection. The causavite agents are corynebacterium species, kytococus sedentarius and dermatophilus con- golensis.2-5 Pitted keratolysis was first reported by Castellani in a Ceylonese patient in 1910, and was confirmed as a unique separate clini- cal entity in the 1930s. The current name, plantar pitted keratolysis, was used to define the clinical presentation.1 Diagnosis can easily be made by means of visual examination and recognition of the characteristic odor.2 In our study, patients were aged between 18-56 years (mean 38.95 years), which correlated with the other reports.6 Pitted keratolysis is observed in males more than females.6-9 In our study, the male to female ratio was 6:4, showing an almost equal predilection. Pitted keratolysis is reported to be more common among barefooted laborers/ farmers, sailors, soldiers and industrial work- ers wearing occluded wet shoes for prolonged periods.1 Ramsey reported pitted keratolysis as a common infection of active feet as sporting activity makes the feet hot and wet.10 In our study, there were no barefoot laborers, farm- ers, sailors or soldiers. Most of our cases were office workers and well-educated people who take care of their personal hygiene. Prolonged use of footwear could be the common factor in these subjects. Interestingly, more than the half of the female patients (58.8%) had a his- tory of regular pedicure and foot care in a spa salon. Moisture and inappropriate hygiene may be the predisposing factors in such patients. Pitted keratolysis is usually asymptomatic but patients may complain of hyperhydrosis, sliminess, malodor and occasionally soreness, itching and pain while walking.11,12 In our study, malodor (100%) was the most commonly reported symptom. In one series, Naik and Singh reported malodor in 70% of patients.6 Malodor could be the most important indica- tion of disease because of its negative impact in office-working conditions. Pain and a burn- ing sensation were reported by almost a quar- ter of the patients (26.8%). Sliminess of the skin was also a common complaint (26.8%). Pruritus was present in only one patient (2.4%). Interdigital intertrigo and paronychia may coexist with pitted keratolysis but these are reported to have no influence on the onset or course of the disease.11 Associated dermato- phyte infections were also evident in 17.1% of our patients. Associated plantar warts and corn was observed in 7.3 and 2.4% of the cases, respectively. Corynebacterial triad (pitted ker- atolysis, erythrasma and trichomycosis ) was not seen in any of the patients in the present study. The other associated diseases were dia- betes mellitus (9.75%), depression (2.4%), and immunosuppression (7.31%) due to chemo - therapy for ovarian carcinoma, and interferon treatment for hepatitis B and C. The predispos- ing factors are known to be a humid climate, poor hygiene, hyperhydrosis, obesity, diabetes, advanced age and immunocompromised host.2 In contrast with the literature, the city where the study took place does not have a hot and humid climate and patients showed a good standard of personal hygene. However, the associated disorders, such as diabetes or immunosuppression, were correlated with the other reports. Pitted keratolysis has been reported to have an excellent prognosis; effective treatment clears both the lesions and the odor in 3-4 weeks time. Topical antibiotics are reported to be effective, easy to use and acceptable by the patients. Recommendations include twice- daily application of erythromycin solution or gel, 1% clindamycin hydrochloride solution, fusidic acid cream and mupirocin cream. Use of systemic antiobiotic may shorten the treat- ment period.1-3 Koc et al. reported topically applied clindamycin and erytromycin to be both safe and effective.13 In a case of Ertam et al., three weeks of oral erythromycin treatment was reported to be effective.14 In our study, only topical treatments were applied in 9 cases whereas 32 patients needed both topical and systemic treatments. Treatment duration was 1-8 weeks (mean 19 days) which was almost twice that reported by Koc et al.13 During the follow-up period, recurrence was observed in 7 (17%) of the patients after one year. Most of the patients (83%) had no recur- rence after one year. This might be because of the increased awareness in avoiding the pre- disposing factors, as well as applying the treat- ments correctly. The common feature of the 7 recurrent cases was the highly hyperkeratotic tissue of the soles. Patients should be warned about the importance of plantar hyperkeratosis in disease development, as under suitable con- ditions, like prolonged occlusion, hyperhydro- sis, and increased skin surface pH, bacterias that cause the disease may proliferate and pro- duce proteinases which in turn destroy the hyperkeratotic stratum corneum, creating pits and causing malodor. Maintenance treatment may be suggested to these high-risk patients. Preventive measures, such as avoiding occlu- sive footwear, not sharing shoes or towels with others, using absorbent cotton socks, and dry- ing feet properly after washing should be rec- ommended. Most of our patients maintained a good standard of personal hygiene and were careful about using shoes, socks or towels but they all prolonged use of occlusive footwear. Conclusions Plantar pitted keratolysis is a disease mostly affecting the soles of the feet. It is a bacterial infection and usually occurs because of pro- longed use of occlusive footwear. Although a lot of people have smelly feet there are not many reports about the real incidence of plantar pit- ted keratolysis. The only reports concern high- risk groups. Our study showed that the inci- dence of pitted keratolysis might be more com- mon than suspected. Instead of seeking med- ical help, people with foot odor might be using over the counter products which mostly contain anti-fungals and anti-perspirants or sometimes ointments which may aggrevate maceration. References 1. Singh G, Naik CL. Pitted keratolysis. Indian J Dermatol Venereol Leprol 2005; 71:213-15. 2. Martin AG, Kobayashi GS. Bacterial dis- eases with cutaneous involvement. In: Freedberg IM, Eisen AZ, Wolff K, et al. Dermatology in general medicine. New Article Table 1. Treatment modalities according to clinical appearance. Symptom N (%) Topical treatment Systemic treatment Malodor-pits 9 (21.9) Erythromycine gel - Malodor-hyperkeratosis-deeper pits 19 (46.4) Erythromycine gel Roxytromycine 10% salicylic acid cream 300 mg/day Malodor-hyperkeratosis-deeper pits-maceration 13 (31.7) Erythromycine gel Roxytromycine 10% salicylic acid cream 300 mg/day 0.01% KMNO4 Solution No n- co mm er cia l u se on ly [page 16] [Dermatology Reports 2012; 4:e4] York: McGraw Hill Inc, 5 th edi; 1999. pp 2203-2204. 3. English JC. Pitted keratolysis. eMedicine J 2003;11:1-7. 4. Woodgyer AJ, Baxter M, Rush-Munro FM. Isolation of Dermatophilus congolensis from two New Zealand cases of pitted ker- atolysis. Aust J Dermatol 1985;26:29-35. 5. LongshawCM, Wright JD, Farrel AM, Holland KT. Kytococcus sedentarius the organism associated with pitted keratoly- sis,produces keratin-degrading enzymes. J Appl Microbiol 2002;93:810-6. 6. Naik CL, Singh G. Clinico epidemiological study of pitted keratolysis. Ind J Dermatol 2007;52:35-8. 7. Schissel DJ. Aydelotte J, Keller R. Road rash with a rotten odor. Mil Med 1999;164:65-7. 8. Gill KA, Buckels LJ. Pitted keratolysis. Arch Dermatol 1968;98:7-11. 9. Morse JM. When a patient presents with malodorus, macerated feet. Podiatry Today 2008;12:26-32. 10. Ramsey ML. Pitted keratolysis. A common infection of active feet. Phys Sport Med 1996;24:1-4. 11. Takama H, Tamada Y, Yano K, et al. Pitted keratolysis. Clinical manifestations in 53 cases. Br J Dermatol 1997;137:282-5. 12. Narayani K, Gopinathan T, Ipe PT. Pitted keratolysis. Indıan J Dermatol Venereol Leprol 1981;47:151-4. 13. Koc E, Arca E, Akar A, Gür AR. Comparison of topical Clindamycine solution with ery- tromycin gel treatment in pitted keratoly- sis. Dermatose 2004;4:37-41. 14. Ertam I, Aytimur D, Yuksel SE. Isolation of Kytococcus sedentarius from a case of pit- ted keratolysis. Ege Tip Dergisi 2005; 44:117-8. Article No n- co mm er cia l u se on ly