Indian Journal of Dermatology
: 2022  |  Volume : 67  |  Issue : 4  |  Page : 481-

Bullous pyoderma gangrenosum occurring on a cesarean section scar

Riko Ishizaki, Miyuki Yamamoto, Toshiyuki Yamamoto 
 From the Department of Dermatology, Fukushima Medical University, Fukushima, Japan

Correspondence Address:
Riko Ishizaki
From the Department of Dermatology, Fukushima Medical University, Fukushima

How to cite this article:
Ishizaki R, Yamamoto M, Yamamoto T. Bullous pyoderma gangrenosum occurring on a cesarean section scar.Indian J Dermatol 2022;67:481-481

How to cite this URL:
Ishizaki R, Yamamoto M, Yamamoto T. Bullous pyoderma gangrenosum occurring on a cesarean section scar. Indian J Dermatol [serial online] 2022 [cited 2023 Mar 22 ];67:481-481
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A 34-year-old woman, who had thrombocytopenia from early pregnancy, had an emergency cesarean section at 36 weeks of pregnancy because of a premature rupture of membrane. On postpartum day 4, she presented bullous lesions on and around the surgical scar with a fever as well as increased levels of C-reactive protein. There were no contact allergens on her abdomen. A wound infection was suspected and antibiotics were administered; however, no improvement of skin symptoms, fever, or inflammatory reaction markers was observed. Physical examination showed palm-sized induration with multiple coalesced tense bullae and erosions with a bilateral symmetrical distribution around the suture line of her cesarean section scar [Figure 1]a. Laboratory testing showed increased white blood cell counts (15,500/μl) and C-reactive protein (28.0 mg/dl). A biopsy from a tense bulla revealed subepidermal intense edema as well as dense and diffuse neutrophil infiltration throughout the dermis [Figure 1]b. Another biopsy from the infiltrative erythema also revealed prominent infiltration of neutrophils and mononuclear cells. Features of vasculitis, epidermal necrosis, and hair follicle destruction were not observed. The abdominal erythema, bullae, and induration were successfully treated with oral prednisolone (20 mg/day), which was gradually tapered and finished within 2 weeks [Figure 2].{Figure 1}{Figure 2}

Pregnancy-associated pyoderma gangrenosum (PG) is rare and tends to affect women in their second and third trimesters. Steele et al.[1] reviewed 26 patients with pregnancy-associated PG, 12 (46.1%) of whom developed PG at the site of caesarean sections between 1 day and 4 weeks after delivery. Alterations in the immune system during pregnancy, i.e. progressive neutrophilia, a placenta-derived granulocyte colony stimulating factor, a balance shift towards Th1 and Th17, and increased serum levels of neutrophil attracting factors, such as granulocyte colony-stimulating factor and granulocyte-macrophage colony-stimulating factor, as well as lower regulatory T-cells at the end of pregnancy[2],[3] might predispose certain patients to PG. Furthermore, surgical invasion by cesarean section triggers the development of PG.

The characteristics of the present case are that bullous lesions developed in an area confined to and around the patient's cesarean section scar. After delivery, her skin lesions were rapidly improved by oral prednisolone (0.5 mg/kg) within a short period. Several cases of PG in association with surgical procedures of cesarean delivery have been reported, suggesting that pathergy reaction may have a triggering role in the induction of PG in patients with susceptible disposition. Post-cesarean section PG is rare but all have been ulcerative type. To our knowledge, this is the first report of bullous type PG on a cesarean delivery scar. However, bullous PG is difficult to differentiate from bullous Sweet's syndrome, and such features are considered an overlap or a transition between both disorders.[4] In the present case, there were no skin lesions such as painful erythematous nodules suggestive of Sweet's syndrome other than abdominal lesions. Most of the cases of neutrophilic dermatosis on the post-cesarean section scar have been reported as PG, rather than Sweet's syndrome, but our case suggests similarities or close relationship of the two representative neutrophilic dermatoses, PG and Sweet's syndrome.

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