| Abstract|| |
Background: Physical differences among human populations may lead to variable prevalence of skin disorders in different ethnicities. Skin infections are one of the important curable and largely preventable categories of skin disorders in the communities. Aim: The purpose of the study was to see the patterns of skin infections in black Africans of Sierra Leone and to compare with other ethnic populations. Materials and Methods: Local blacks of all age groups presenting in Dermatology out patient department of Pak Field Hospital (established as a part of UN peacekeeping mission in Sierra Leone) were included (from Nov 2004 to Oct 2005). Relevant clinical history and physical examination was done. Laboratory investigations were carried out when indicated. Skin diseases were broadly classified into two major categories i.e., infective and noninfective. Among infective, sexually transmitted infections were again separated. Nonblack settlers in the area and UN troops were not included in the study. Data was recorded and analyzed by Microsoft Excel program. Results: 3011 patients belonging to different local tribes having a variety of skin disorders were seen. Patients were of all ages and both sexes ranging from one month to 73 years of age. The Infective skin disorders were seen in 61.7% patients and most prevalent were superficial fungal infections (41.2%) followed by, sexually transmitted infections (9.9%) and parasitic infections (6.5%). Bacterial and viral infections were rare and so was the scabies. More than 90% parasitic infections were onchocerciasis with full spectrum of cutaneous manifestations. Conclusion: Pattern of skin infections in blacks varies considerably from other ethnic races. Environmental factors, geographical location and free existence of vector for onchocerciasis in West African region, possibly have a significant influence in this variable prevalence.
Keywords: Black Africans, cutaneous infections, ethnic groups, pattern of skin disorders
|How to cite this article:|
Bari A. Pattern of skin infections in black Africans of Sierra Leone (West Africa). Indian J Dermatol 2007;52:30-4
| Introduction|| |
A vast majority of the world's population consists of individuals with pigmented skin (skin types IV, V and VI). An individual with an olive skin tone, also characterized as beige or lightly tanned, is classified as having type IV skin; those with brown skin as type V; and black skin as type VI. These skin types rarely or never burn on sun exposure and tan readily., People with these skin types constitute a wide range of racial and ethnic groups including Africans, African Americans, African Caribbeans, Chinese and Japanese, Hispanics and certain groups of fair-skinned persons (e.g., Indians, Pakistanis, Arabs). The skin phototype (SPT) system, developed by Fitzpatrick, is predicated on the reactions or vulnerability of various types of skin to sunlight and ultraviolet radiation (UVR). Darker skin differs from Caucasian skin in its reactivity and disease presentation. Ethnic differences in skin properties may explain racial disparities seen in dermatologic disorders. Some conclusions have so far been made about racial and ethnic differences in skin structure, physiology and dermatologic disorders. These include differences in epidermal melanin content, melanosome dispersion, hair structure, fibroblast and mast cell size and structure in people of color compared with fair-skinned persons.,4],, The epidemiology of skin diseases in people of color has not been extensively studied. Many skin diseases (e.g., acne vulgaris; eczematous dermatitis; infections caused by bacteria, fungi or viruses) are common to most people of color-blacks, Asians, Hispanics/Latinos and Native Americans. A variety of cutaneous infections are commonly seen in blacks. Some of these infections are prevalent in blacks because of geography, environment and low socioeconomic status causing over-crowding, malnutrition and poor or delayed access to medical care.,,,, The purpose of the study was to see the patterns of skin infections in the Eastern province of Sierra Leone. Sierra Leone is located at west most corner of West Africa, along the costal line of Atlantic Ocean having high humidity and heavy rainfall.
| Materials and Methods|| |
Local black patients of all age groups belonging to eastern province (Kenema) of Sierra Leone presenting with any skin disorder were included. Nonblack settlers in the area and UN troops were not included in the study. Majority reported from vicinity of Kenema city in routine outdoor and a significant number was also encountered from some distant towns of the district in four free medical camps. A thorough clinical history and physical examination was done. Laboratory investigations (Microscopic fungal exam, X-rays, USG, hematological profiles, serological tests for syphilis and tests for HIV, etc.) were also carried out when indicated. Diagnosis of each skin disorder was made on clinical ground and appropriate laboratory support. Clinically, patients were broadly divided into two categories; infective and noninfective. Sexually transmitted infections were further separated from other skin infections. Patients were managed and followed up accordingly. Data was recorded and analyzed by Microsoft Excel program.
| Results|| |
A total of 3011 patients belonging to different local tribes having a variety of skin disorders were seen during the study period. Patients belonged to all ages and both sexes ranging from one month to 73 years of age. Sex ratio was almost equal (48.7% males and 51.3% females). Vast majority were from very low socioeconomic group (96%). 61.7% skin disorders were infective and 38.7% noninfective in nature. Among infective disorders 9.9% were sexually transmitted infections (STIs) and rest 51.8% were non-STIs cutaneous infections. The most prevalent infections seen were fungal infections (41.2%) followed by parasitic (6.5%). Bacterial and viral infections were rare and so was the scabies. More than 90% parasitic infections happened to be onchocerciasis with full spectrum of cutaneous manifestations. Different categories of skin infections along with frequency of their occurrence are shown in [Figure - 1], while composition of individual groups is given in and [Table - 1]. Some of the infective lesions are also shown in [Figure - 2],[Figure - 3],[Figure - 4],[Figure - 5],[Figure - 6],[Figure - 7],[Figure - 8],[Figure - 9].
| Discussion|| |
Disease pattern in a given population is generally determined by different ecological and socioeconomic factors., Black skin, if on one hand, is a blessing as it relates to sun damage and aging, on the other hand it can be a curse for being vulnerable for excess melanin production (resulting in dark patches) or excess collagen production (resulting in keloids/hypertrophic scars) in reaction to skin infections, minor trauma or even a scratch.,, Various cutanoeus infections are prevalent in people of African region due to geographical, environmental and social factor., Our study demonstrated a very high prevalence (61.7%) of infective disorders in the study population when compared with other studies in Asians and Caucasians.,,,,,, Fungal infections (42%) were the commonest. Geographical factors such as season and climate (heavy rainfall for 9-10 months in a year) could contribute to this high incidence of fungal infection. Although we encountered almost all types of superficial and few cases of deep fungal infections, but most common of all was tinea versicolor as expected in a tropical and humid place like Sierra Leone. Second highest prevalence was of sexually transmitted infections (STIs). Most STIs, including HIV infections have shown a marked decrease in western world during last couple of decades, but black population of all poverty driven countries of African region is still disproportionately affected due to a number of reasons., In our study, a significant number of STIs was expected because the target population belonged to an area that was affected by a decade long brutal civil war. Most frequent among STIs, were gonorrhea and syphilis and seropositivity for HIV was seen only in 0.8%. This low seropositivity was due to the fact that, due to limited availability of HIV screening tests with us, we did HIV testing only in high-risk patients (patients with other STIs or having suggestive symptoms). Our main aim was to see the pattern of non- STIs cutaneous infections. Onchodermatitis was the next common disease in our study. It is endemic and a major public health problem in many countries in Africa, including Sierra Leone.  It is a chronic, multi-systemic parasitic disease caused by the nematode Onchocerca volvulus . The main vector in most of Africa is a black fly ( Simulium damnosum). We encountered patients with whole clinical spectrum (acute papular onchodermatitis, chronic papular onchodermatitis, chronic lichenified onchodermatitis, sowda, leopard spotting, lizard skin, hanging groin and onchocercoma) of the disease., Considering endemic nature, increased prevalence of this parasitic disease in our study was expected but to our satisfaction we could find the whole clinical spectrum in our patients. Surprisingly, we found significantly less number of bacterial, viral and other parasitic (except onchodermatitis) infections, when we compared with other studies.,,,,,, Interestingly, there was also no case of cutaneous tuberculosis or leprosy. This was in contrast to findings in Asian communities.,, In a very recent study conducted in a coastal city of Mangalore in India (having the similar hot humid climate as in Kenema city of Sierra Leone in our study) fungal infections constituted the commonest infective dermatoses and split up of fungal infections was again similar to our study but they also had frequent bacterial and viral infections along with cases of scabies and leprosy in contrast to our study. We initially expected high prevalence of infections in our study population because of extreme poverty, overcrowded living and very low socioeconomic and hygienic conditions prevailing in the community. The explanation of this significantly less frequent infection rate may be the existence of some naturally occurring antiinfective agent in their diet, secretion of some potent antiseptic/antiinfective agent in their sweat or some genetic factors contributing to the resistance against these infections. Hot humid weather could be another reason for decreases prevalence of viral infections especially with herpes virus. These observations need to be investigated on a wider scale. We believe that most of the prevalent infections (tinea infections and onchodermatitis) in our study occurred because of geography (high temperatures, humidity), environment and free existence of vector for onchocerciasis. Low socioeconomic status causing over-crowding, malnutrition and poor or delayed access to medical care and some cultural practices probably contributed less towards causing cutaneous infections, as reflected by very few cases of scabies, chicken pox and impetigo, etc.
| Conclusion|| |
Racial or ethnic differences in cutaneous infections pattern are predicated on geography, biology genetics and culture in addition to geopolitical and socioeconomic environment. Physicians managing black patients with dermatologic infections should be aware of and must consider all the factors that initiate, aggravate and perpetuate cutaneous infections under these conditions.
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[Figure - 1], [Figure - 2], [Figure - 3], [Figure - 4], [Figure - 5], [Figure - 6], [Figure - 7], [Figure - 8], [Figure - 9]
[Table - 1]