INTRODUCTION

Systemic lupus is an autoimmune, systemic disease of unknown etiology, characterized by multivisceral involvement, with a chronic course of relapses interspersed with multiple remissions. It is a cosmopolitan disease, affecting young women in particular [1]. The systemic nature of this disease explains the clinical polymorphism that characterizes it, with several modes of revelation. This variability in the circumstances of discovery and the often-misleading nature of initial presentations, especially in the absence of cutaneous signs, make diagnosis difficult, especially in Africa, where there is a high degree of diagnostic erraticism, further encouraged by inadequate technical resources [2]. The incidence and prevalence of lupus vary depending on sex, age, ethnic origin, and time. Indeed, the incidence of the disease is highest in the northern United States, where it is 23.3/100,000 people/year [3]. In Africa, it is lower, estimated to be 0.3/100,000 people/year on average [4]. In Senegal, the largest series are carried out at internal medicine departments. We, therefore, thought it appropriate to review the epidemiological, clinical, paraclinical, therapeutic, and evolutionary aspects of systemic lupus at the Dermatology Department of CHU Aristide Le Dantec from January 2009 to December 2019.

MATERIALS AND METHODS

This was a retrospective, descriptive study conducted at the Dermatology Department of Aristide Le Dantec Hospital in Dakar from January 2009 to December 2019. All records of patients hospitalized during the study period, regardless of age, for systemic lupus, whose diagnosis was accepted according to the modified ACR criteria [5] or the new SLICC (Systemic Lupus International Collaborating Clinics) group criteria [6], were included. Incomplete and those not meeting international diagnostic criteria were not included in the study. Data were collected using a pre-established survey form containing clinical, paraclinical, therapeutic, and evolutionary data. Data was entered using Sphinx V5 software and analyzed using Excel 2013. We performed cross-tabulations of several variables using the Pearson chi-squared test, and the association was considered statistically significant when p was strictly less than 0.05.

RESULTS

During the study, we identified 3,400 cases of patients hospitalized at the dermatology department of Aristide Le Dantec Hospital, all pathologies combined, including 290 cases of connective tissue diseases and 75 cases of systemic lupus. This represents a hospital frequency of 2.2% and a frequency of 25.86% among connective tissue diseases.

The average age was 31, with extremes of 14 and 59. Fig. 1 illustrates the distribution of lupus cases by age group, with 68 women and 7 men, giving a sex ratio of 9.7. The patient’s profession was provided in 52% of the cases (n = 52) (Table 1). A medical history was noted in 15% (n = 11). Abortion was noted in 19% of the cases (n = 14), diabetes in 4% (n = 3), hypertension in 4% (n = 3), and rheumatoid arthritis in 3% (n = 2). Toxidermia was associated with systemic lupus in 6.66% (n = 5 cases). The mean duration of systemic lupus before diagnosis was 31.6 months, with extremes of 1 and 168 months. Herbal medicine was used as first aid in 17% of the cases (n = 13). Dermatological manifestations were constant, dominated by chronic lupus lesions found in 40% of the cases (Fig. 2a), followed by acute lupus lesions in 36% (Fig. 2b) and subacute lupus lesions in 33% (Fig. 2c). Table 1 shows the frequency of dermatological manifestations.

	Figure 1: Age distribution in systemic lupus.
	Figure 2: (a) Discoid lupus lesions in systemic lupus. (b) Vespertilio erythema in systemic lupus. (c) Subacute lupus in the psoriatic form. Collection: Dermatology Department of Aristide Le Dantec Hospital.

Table 1: Distribution of the dermatological manifestations in systemic lupus.

Joint manifestations were present in 34.4% (n = 55), with non-deforming inflammatory polyarthralgia in 3.5% (n = 52), deforming inflammatory polyarthralgia in 0.62% (n = 1), and true non-deforming arthritis in 1.25% (n = 2). Muscular manifestations were noted in 7.5% (n = 9), with isolated myalgias in 2.5% (n = 3) and muscular syndrome in 5% (n = 6). Uro-nephrological disorders were represented by urinary signs (9.33%) such as dysuria (4%), pollakiuria (2.66%) and mictional burning (2.66%). Pleuropulmonary involvement was noted in 12% of the cases (n = 9), with the signs being crepitus rales in 5.49% (n = 5), condensation syndrome in 2.19% (n = 2), and liquid pleural syndrome in 2.19% (n = 2). Cardiovascular disorders were present in 5.33% of the cases, with regular tachycardia in 2.66% (n = 2) and pericardial friction in 1.33% (n = 1). Neuropsychiatric manifestations were present in 10.66% (n = 9) and included generalized convulsions in 4% (n = 3), psychic agitation in 2.66% (n = 2), isolated headache in 2.66% (n = 2), mood disorder in 1.33% (n = 1) and confusional syndrome in 1.33% (n = 1). Ophthalmological manifestations were noted in 2.66%, such as blurred vision, and ENT signs in 1.33%. Paraclinically, anemia was present in 90.66% (n = 68), lymphopenia in 50.66% (n = 38), neutropenia in 20% (n = 30), and leukopenia in 1.33% (n = 1). The direct Coombs test was positive in 4% (n = 18). Sedimentation rate (ESR) was performed in 89% (n = 67) and accelerated in 91% (n = 61). CRP was performed in 93.33% (n = 70) and positive in 33.33% (n = 35). A non-specific biological inflammatory syndrome was noted in 34.6% of the cases (n = 26). Autoantibodies were requested in 60% of the cases (n = 45), among which anti-ECT antibodies were positive in 56% (n = 42), anti-nuclear antibodies were positive in 7% (n = 6) with homogeneous fluorescence in 4% (n = 3) and speckled fluorescence in 3% (n = 2). Anti-DNA-native antibodies were positive in 12% (n = 9).

Serum complement was requested only once and showed total hypocomplementemia. As regards muscle enzymes, lacticodehydrogenase (LDH) was positive in 7% of the cases (n = 5), CPK in 5.3% (n = 4) and AST in 15% (n = 11). Uro-nephrological abnormalities included 24-hour proteinuria, which was positive in 53% (n = 40). Hematuria was noted in 15% (n = 11) and leukocyturia in 24% (n = 18). Interstitial syndrome was found on radiology in 12% (n = 9). Cardiac ultrasound abnormalities included pulmonary hypertension in 5% (n = 4) and pericardial effusion in 9% (n = 7). Pathological examination of renal biopsy specimens showed diffuse proliferative glomerulonephritis class IV in 1.3% (n = 1), extra-membranous glomerulonephritis class V in 3% (n = 2) and both interstitial and vascular involvement without glomerular involvement in 1.3% (n = 1). Table 2 lists the various drug treatments employed. Figure 3 summarizes the main evolutionary trends. Infectious complications were noted in 27% (n = 20), the main sites being urinary (12%), cutaneous (9%), pulmonary (3%), and vaginal (3%). Aseptic osteonecrosis of the femoral head was noted in 3% (n = 2), and nephrotic syndrome in 1% (n = 1). Among patients with good evolution, 29% (n = 22) presented a new relapse during their follow-up. The decompensation factors found were unplanned pregnancy in 11% (n = 8), irregular follow-up in 6.6% (n = 5), the discontinuation of treatment in 5% (n = 4), and reduction in corticosteroid doses in 1% (n = 1).

Table 2: The various therapeutic means used in systemic lupus.

Figure 3: The evolutionary stages of systemic lupus.

DISCUSSION

We conducted a retrospective study at the Dermatology Department of Aristide Le Dantec Hospital in Dakar over the period from January 2009 to December 2019. Our work presented some limitations that would be important to take into account when interpreting the results. One limitation was that the study population consisted solely of inpatients. This created a selection bias since a significant number of patients were followed up on an outpatient basis. Secondly, a large number of patients were not included in the study due to the absence of clinical and/or paraclinical data, which meant that the classification criteria could not be met. A total of 75 cases of patients hospitalized for systemic lupus were collected during this period, representing an annual frequency of 7 cases per year. During the same period, scleroderma was more frequent, with 94 cases (32.4% of all cases with connective tissue diseases collected), in contrast to other studies conducted in Senegal at dermatology departments, where it was the most frequent [7–9]. This situation could be explained by a selection bias, given the large number of unexploitable cases labeled as systemic lupus. However, this frequency seems to be higher in the Maghreb and Europe [10–12]. Our series consisted mainly of young subjects. This result is compatible with the main series in the literature [10,13–17]. We also noted two cases of systemic lupus with a pediatric onset. These were two female children aged 14 and 15, respectively. Pediatric-onset lupus is a rare disease, diagnosed before the age of 16 in 15–20% of cases [18]. Our study showed a strong female predominance, with a sex ratio of 4.2, in favor of females. The predominance of females in systemic lupus could be explained by the role of hormonal factors, particularly, estrogen, which has an immunostimulatory effect on the immune system via receptors present on the surface of immune cells. This result was in line with the literature, in which the sex ratio varies between 6 and 17 [8,10,13,15,16].

Our study showed the importance of traditional medicine for African populations, with herbal medicine being the first line of treatment. This fact is linked, above all, to ancestral beliefs and encouraged by widespread media coverage of the practice of traditional medicine. This is a major factor in delayed diagnosis, as evidenced by the average length of time taken by our patients to progress. Dermatological manifestations were present in all patients. They were dominated by discoid lupus lesions (40%). These results were in line with the findings of some studies describing the peculiarities of lupus on black skin, with a greater frequency of discoid lupus lesions and a rarity of photosensitivity [19,20]. The frequency of malar erythema, which is characteristic of systemic lupus, was comparable to the result gathered by Kane et al. (33.9%) and much lower than in the North African and European series, in which it was found with a frequency of 62% and 58%, respectively [10,16]. Photosensitivity is more frequent in Caucasians, where it has been reported to be between 10% and 50% [21]. Alopecia was dominated in our series by the scarring type (18.6%), in line with the frequency of discoid lupus. This result was close to that gathered by Dioussé et al. (29.4%), whereas it was lower than that by Kane et al. (35.7%) and Ndiaye et al. (41%) [5,7,13]. Articular manifestations came second after dermatological disorders, whereas they predominated in the series by Kane et al. (89.2%) and Ka et al. (97%) [13,22]. However, these studies were conducted at internal medicine departments. Uro-nephrological involvement, dominated by urinary signs, is thought to be related to urinary tract infections, as shown by the frequency of positive ECBU (8%). Glomerular nephropathy was noted in 53.33%, based on 24-hour proteinuria positivity. However, the interpretation of the 24-hour proteinuria positivity must take into account the result of the ECBU. This frequency of nephropathy in systemic lupus is in line with the literature, where it is estimated to fall between 40% and 60% [23–25]. Renal histology was conducted in only 2% of cases (n = 7), revealing lupus glomerulonephritis in 85.71% (n = 6), with class I and V predominating (33.33% for each class). Only one case of interstitial and vascular involvement was recorded. However, given the especially limited number of renal biopsies performed in our study, it was difficult to obtain a true mapping of nephropathy classes. However, the literature describes that WHO classes III and IV are the most frequent [26–28].

The involvement of other viscera, notably muscular, cardiovascular, pleuropulmonary, and neuropsychiatric, was less frequent, in line with previous studies.

Anemia was the most frequent hematological abnormality. The origin of anemia in systemic lupus is often multifactorial and non-specific. In contrast, hemolytic anemia characteristic of systemic lupus was noted in only 24% of lupus patients, more frequently than in Louzir’s study (6.7%) and the North American series (18%) [10,28].

Inflammatory syndrome, defined by the association of an accelerated sedimentation rate and an increase in an inflammatory protein such as C-reactive protein, usually accompanies relapses [29]. It was present in 33.66% of the patients in our study. Testing for autoantibodies is an important element in systemic lupus. Among these antibodies, anti-Sm antibodies, highly specific to systemic lupus, were positive in 37.33% of the cases. Native anti-DNA antibodies, highly specific for systemic lupus, were observed in 12% of lupus patients, lower than the Tunisian and European series [10,28]. This could be explained by the low rate of screening for these antibodies in our study (12.41%). Anti-U1 RNP antibodies were positive in 22.66% of our cases. They are the serological marker of mixed connectivitis but are also found in other connectivities [30].

All our patients were treated with oral corticosteroids at an initial dose ranging from 0.5 to 1 mg/Kg. Injectable corticosteroids in bolus form were used in 4% of the cases and corresponded to severe attacks of systemic lupus. Adjuvant treatment, including a proton pump inhibitor (PPI), calcium + vitamin D and potassium supplementation, was combined with corticosteroid therapy in all patients. Dermocorticoids were frequently prescribed (74.66%), due to skin lesions. Hydroxychloroquine was the second most often prescribed specific molecule in our study, after corticoids. As an immunomodulator, it has well-validated indications in systemic and chronic lupus in rheumatoid arthritis [31]. On the other hand, none of our patients received biotherapies, due to the unavailability and, above all, inaccessibility of these often-costly treatments, if we take into account our patients’ low socio-economic level. The prescription of other treatments such as antibiotics, antifungals, and antivirals testify to the existence of infectious complications, which may be either related to the systemic lupus itself, or the side-effects of immunosuppressive drugs.

Patient outcome was good in 43.3% of the cases of connective tissue disease, an assessment made on the basis of improvement in early clinical signs and sometimes paraclinical elements. Mortality was 4% in our study, compared with 13% in the Tunisian series [10]. The main causes of death were hemorrhagic syndrome due to thrombocytopenia (1 case), respiratory distress due to pulmonary embolism (1 case), and the after-effects of aseptic osteonecrosis of the femoral head (1 case). We found no correlation between socio-economic level and the occurrence of death (p = 0.392).

CONCLUSION

Our study showed the frequency of systemic lupus in black phototypes. Its particularity lies in the delay in diagnosis, which is correlated with visceral damage, hence the importance of early diagnosis, which requires a good knowledge of the disease.

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