Immune and barrier characterization of atopic dermatitis skin phenotype in Tanzanian patients.

BACKGROUND: Atopic dermatitis (AD) is a common disease, with particularly high prevalence found in Africa. It is increasingly recognized that patients with AD of different ethnic backgrounds have unique molecular signatures in the skin, potentially accounting for treatment response variations. Nevertheless, the skin profile of patients with AD from Africa is unknown, hindering development of new treatments targeted to this patient population. OBJECTIVE: To characterize the skin profile of patients with AD from Africa. METHODS: Gene expression studies, including RNA sequencing (using threshold of fold change of >2 and false discovery rate of <0.05) and real-time polymerase chain reaction, were performed on skin biopsies of Tanzanian patients with moderate-to-severe AD and controls. RESULTS: Tanzanian AD skin presented robust up-regulations of multiple key mediators of both T helper 2 (TH2) (interleukin 13 [IL-13], IL-10, IL-4R, CCL13,CCL17,CCL18,CCL26) and TH22 (IL22, S100As) pathways. Markers related to TH17 and IL-23 (IL-17A, IL-23A, IL-12, PI3, DEFB4B) and TH1 (interferon gamma, CXCL9,CXCL10,CXCL11) were also significantly overexpressed in AD tissues (FDR<.05), albeit to a lesser extent. IL-36 isoforms revealed substantial up-regulations in African skin. The barrier fingerprint of Tanzanian AD revealed no suppression of hallmark epidermal barrier differentiation genes, such as filaggrin, loricrin, and periplakin, with robust attenuation of lipid metabolism genes (ie, AWAT1). CONCLUSION: The skin phenotype of Tanzanian patients with AD is consistent with that of African Americans, exhibiting dominant TH2 and TH22 skewing, minimal dysregulation of terminal differentiation, and even broader attenuation of lipid metabolism-related products. These data highlight the unique characteristic of AD in Black individuals and the need to develop unique treatments targeting patients with AD from these underrepresented populations.

Skin diseases in pediatric patients attending a tertiary dermatology hospital in Northern Tanzania: a cross-sectional study.

BACKGROUND: Skin diseases affect 21-87 % of children in developing countries in Africa. However, the spectrum of the skin diseases varies from region to region due to several factors such as genetics, socioeconomic and environmental. The aim of this study was to determine the spectrum of childhood skin diseases in Tanzania. METHODS: We conducted a prospective hospital- based cross-sectional study between September 2012 and August 2013 at a tertiary referral dermatology clinic. Children younger than 14 years presenting with new skin conditions were recruited. Diagnosis was mainly done clinically, but if the diagnosis was not clinically clear, further investigations were undertaken accordingly. RESULTS: A total of 340 patients were recruited of which 56 (16.5 %) had more than one skin condition. Both genders were equally affected. Infections and infestations accounted for the majority (43.5 %, n = 177) of the skin conditions followed by eczematous dermatitis (28.5 %, n = 116) and pigmentary disorders (7.4 %, n = 30). Among the 152 infectious skin diseases, fungal infections predominated (50.7 %, n = 77) in the infectious group followed by bacterial (29.6 %, n = 45), and viral (19.7 %, n = 30). CONCLUSIONS: Skin infections are still the main cause of dermatological consultations in children although with a reduced prevalence. Inflammatory skin conditions are increasing and can be attributed to improved socioeconomic status and HIV pandemic.

Skin flora: Differences between people affected by Albinism and those with normally pigmented skin in Northern Tanzania - cross sectional study.

BACKGROUND: Skin flora varies from one site of the body to another. Individual's health, age and gender determine the type and the density of skin flora. METHODS: A 1 cm² of the skin on the sternum was rubbed with sterile cotton swab socked in 0.9% normal saline and plated on blood agar. This was cultured at 35 °C. The bacteria were identified by culturing on MacConkey agar, coagulase test, catalase test and gram staining. Swabs were obtained from 66 individuals affected by albinism and 31 individuals with normal skin pigmentation. Those with normal skin were either relatives or staying with the individuals affected by albinism who were recruited for the study. RESULTS: The mean age of the 97 recruited individuals was 30.6 (SD ± 14.9) years. The mean of the colony forming units was 1580.5 per cm2. Those affected by albinism had a significantly higher mean colony forming units (1680 CFU per cm²) as compared with 453.5 CFU per cm² in those with normally pigmented skin (p = 0.023). The skin type and the severity of sun- damaged skin was significantly associated with a higher number of colony forming units (p = 0.038). CONCLUSION: Individuals affected by albinism have a higher number of colony forming units which is associated with sun- damaged skin.

Acral peeling skin syndrome in two East-African siblings: case report.

BACKGROUND: Acral peeling skin syndrome is a rare autosomal recessive genodermatosis due to a missense mutation in transglutaminase 5. The skin peeling occurs at the separation of the stratum corneum from the stratum granulosum. CASE PRESENTATION: We present a case of two siblings who developed continuous peeling of the palms and soles from the first year of life. This peeling was more severe on the soles than palms and on younger sibling than elder sibling. Peeling is worsened by occlusion and sweating. CONCLUSIONS: Sporadic cases of Acral Peeling Skin Syndrome occur in African population. There is variability in time of presentation and clinical severity even within families.

Dermoscopic Features of Psoriasis, Lichen Planus, and Pityriasis Rosea in Patients With Skin Type IV and Darker Attending the Regional Dermatology Training Centre in Northern Tanzania.

BACKGROUND: Papulosquamous skin diseases can be challenging to diagnose, especially in dark skin. Dermoscopy is reported to be helpful, but few data are available on its use in skin type IV or darker. OBJECTIVE: To describe dermoscopic features in plaque-type psoriasis (PP), lichen planus (LP), and pityriasis rosea (PR) patients attending the Regional Dermatology Training Centre in Moshi, Northern Tanzania, and to compare findings with published data. METHODS: A descriptive cross-sectional study was conducted at a tertiary hospital from October 2016 to June 2017. Fifty-six patients with PP, 25 with LP, and 9 with PR were enrolled consecutively. Clinical diagnosis was confirmed with histopathology in 74.4%. Dermoscopic vascular and nonvascular features from 225 lesions were analyzed. RESULTS: Of the 90 patients enrolled, 58.9% were male and the median age was 50 (interquartile range 32.8-60.0) years. In PP lesions, red dots were found in 64.2% and white scale in 45.5%. In LP lesions the background was violet in 45.5% and 58.2% revealed Wickham striae. In PR lesions a dull red background was found in 50.0%, white scale in 83.3%, but no vessels were detectable. CONCLUSION: Dermoscopy features in PP, LP, and PR in dark skin are mostly similar to those in light skin.