Discussion
Striae Distensae, are common skin lesions characterized by linear atrophic plaques directed perpendicularly to the skin.2,4 They represent either, benign physiological changes as during pregnancy and adolescence, or a pathological sign of certain diseases.4 Rarely, bullae can develop within the striae.5,6,7 They exhibit lower hydration levels in both the epidermis and dermis, along with reduced dermal echo density and elasticity compared to normal skin.10 A rare variation of stria distensae, Bullous Stria Distensae, is characterized by the development of tense bullae within the stria. Almashat et al. suggested that patients with nephrotic syndrome and chronic steroid use may trigger bullous stria development, particularly in cases of anasarca.2,7 The pathogenesis of BSD remains uncertain, however, it has been hypothesized that mechanical stress on the dermis leads to the rupture of the dermal vasculature and subsequent bullae formation. Seshadri et al. additionally proposed that the weak tensile strength of the stria may contribute to the build-up of fluid within them. Besides, as the size of the stria increases, the likelihood of fluid accumulation also increases.3 Masoud et al. reported that patients on oral steroids, developing generalized body edema, tend to accumulate fluid, particularly in the striae. They further put forward a hypothesis that the phenomenon might result from the combined effect of both anasarca and steroid medication. Glucocorticoids were thought to enhance the collagen breakdown, reducing tensile strength allowing fluid to accumulate preferentially from anasarca within the stria spaces, forming fluid-filled sacs.5
In our case, a 17-year-old female with nephrotic syndrome presented with an emergence of bullous lesions on her abdominal striae. The distinctive histopathologic characteristics of edematous dermis with a slightly thin and horizontally oriented dermal collagen confirmed the diagnosis of BSD. With regard to fluid aspiration culture and sensitivity report, the bullae were found to be sterile, which is consistent with a previous report by Seshadri et al.3 To the best of our knowledge, this is the fourth case reported the occurrence of bullous skin disease in a patient with nephrotic syndrome documented in the literature. The rapid weight gain and the presence of ascites in our patient may have resulted in increased mechanical stress on the dermis, which contributed to the development of BSD. The coexistence of lipodystrophy and hypoproteinemia in nephrotic syndrome may have further weakened dermal collagen, potentially increasing the patient’s susceptibility to BSD development.2,4 In our case and other reported cases, patients had hypoalbuminemia due to different pathologies and striae Distensae. Three of the reported cases were associated with receiving high or fluctuating dose of systemic steroid for varying duration.2,3,7 This phenomenon can be explained by the effect of decreased oncotic pressure on weakened or atrophic layers of skin.6 In this clinical context, differential diagnosis includes autoimmune bullous diseases, which can be ruled out through direct immunofluorescence. However, managing the underlying medical illness with diuresis can lead to spontaneous resolution, as puncture and aspiration of fluids alone would result in rapid fluid reaccumulation. Jogova et al. also highlighted that upon treatment with diuresis, flattening of the fluid-filled stria were notable.4 Certainly, BSD management is primarily centred around addressing the underlying cause. In our case, the administration of diuretics to manage her ascites played a role in reducing the mechanical stress on the dermis, which resulted in a gradual resolution of the bullae. The strength of our case report lies in its rarity, as we are only the second case report highlighting the potential advantage of employing diuresis as a management approach for BSD. It is crucial to attain optimal management of nephrotic syndrome to minimize the risk of BSD, considering the ongoing fluid shifts and the chronic use of corticosteroid. Future research is needed to enhance the understanding of the underlying pathogenesis of BSD. Additionally, further clinical trials are imperative to thoroughly assess the efficacy of diuresis as a viable management approach for BSD in order to establish the optimal management approaches for treating the condition. By shedding light on this barely explored area, the novelty of our findings contributes to enhancing the understanding of the potential therapeutic options for addressing bullous stria distensa.