Introduction
Superficial fungal infections (SFIs) affect 20–25% of the world’s population.1 The most prevalent causative agents of SFIs are dermatophytes, yeasts and molds.2 A significant variation in the prevalence and pattern of SFIs was evident from studies from Asia2, Africa3, Europe4 and North America. 5 The objectives of this study were to determine clinical patterns of SFIs among patients attending a dermatology clinic in Upper Egypt; and identify demographic characteristics associated with those infections.
Materials and Methods
This study was conducted in the Dermatology clinic at Sohag University Hospital, Upper Egypt, between April 2014 and March 2015. The study included patients with diagnosis of SFIs following examination by a single dermatologist. Skin scrapings, hair plucking and nail clippings were taken from infected areas, treated with 10-20% potassium hydroxide (KOH) and examined microscopically for hyphae and/or arthroconidia.
Housing data included number of persons per room and presence of domestic animals. Categorical data were presented as frequencies and percentages and compared by chi square test. Statistical significance was considered at p < 0.05.
Results
SFIs were diagnosed in 800/7680 (10.4%) of patients attending the dermatology clinic. Direct KOH microscopy yielded positive results (hyphae and/or arthroconidia) in 522/720 (72.5%). The median (interquartile range) of patient's age was 16 (9, 30) (range from 1 to 57) years. 654/800 (81.75%) of cases reported rural residence and 146/800 (18.25%) reported urban residence. Distribution of patients with SFIs was shown in Table 1. Tinea was diagnosed in 614/800 (76.75%) of cases.
Family history of a co-existing similar condition was recorded in 148/800 (18.5%) of cases, with tinea capitis reported in 85/148 (57.43%). Overcrowding (presence of 3 or more persons per room) was associated with increased frequency of tinea corporis (147/249 (59.04%), tinea capitis (145/244 (59.43%), tinea pedis (58/89 (65.17%), tinea unguium (19/27 (70.37%) and pityriasis versicolor (95/149 (63.76%). Tinea corporis and tinea capitis were prevalent among patients having domestic animals [157/249 (63.05%) and 130/244 (53.28%); respectively]. Diabetes mellitus (DM) was recorded in 14/37 (37.8%) cases with candidiasis and 17/763 (2.23%) of other SFIs.
Discussion
Approximately, 1/10 of patients attending a dermatology clinic in Upper Egypt had SFIs. Tinea was the most prevalent clinical pattern of SFIs, and accounted for more than 3/4 of the cases. The predominance of tinea, over other SFIs, was a constant finding of epidemiological studies from China2, Nigeria3, France4, and USA.5 Tinea corporis was the commonest clinical subtype of tinea, in this study, and most cases were found among adolescents and adults, with female to male ratio of 3:2.
Tinea capitis was the second commonest pattern of SFIs, in this study, with a tendency towards greater affection of children and predominance among males (2.5:1). The predominance of tinea capitis among children had been attributed to the low level of fungistatic fatty acids in skin at the early age before puberty.3 In the present study, tinea pedis accounted for 11.13% of all cases of SFIs. In USA, tinea pedis was detected in 3.87% of the surveyed population, and ranking at the top of dermatophytoses.5
In this study, pityriasis versicolor accounted for approximately 1/5 of SFIs, and more than 2/3 of patients were adults. Increased prevalence of pityriasis versicolor among adults has been related to post-pubertal enhancement in the metabolism of lipophilic yeasts of Malassezia.6 Approximately, 2/3 of patients with candidiasis, in this study, were females and 1/3 had DM. Females usually harbor candida species in the vagina, or on glabrous skin. 7 Also, DM was found to increase the incidence of yeast infections.8
Interestingly, majority of patients with SFIs were resident of rural areas and most of cases with tinea corporis and tinea capitis reported overcrowding conditions and/or presence of domestic animals. Variations in epidemiologic features of SFIs in different studies may be due to differences in study designs, inclusion criteria, investigative tools, environmental factors and socio-economic standards. Periodic epidemiological analysis of these conditions may be important to ensure their effective control.
Despite interesting findings in this study, some limitations were noted. First, hospital-based nature of the study did not enable us to determine the true prevalence and risk factors of SFIs. Second, mycological evaluation was limited to direct microscopy, therefore, we were not able to identify specific fungal species responsible for SFIs.