Pustular psoriasis of pregnancy in a patient whose dermatosis showed features of acute generalized exanthematous pustulosis
Authors: Goldberg Green Michelle , Bragg Jennifer , Rosenman Karla S. , Keltz Pomeranz Miriam 
Published: February 2009

A 23‐year‐old pregnant woman at 38 weeks of gestation presented with a 2‐day history of a red eruption on her abdomen and upper thighs. The patient had applied baby oil to her abdomen a few days earlier, but she denied using any other topical products. Her only medications were prenatal vitamins and iron, which she had been taking since the beginning of her pregnancy. The clinical impression was contact dermatitis, and she was started on topical Sarna lotion (containing 0.5% camphor and 0.5% menthol) after she declined topical steroids.

 Three days later, she presented to the dermatology clinic with worsening pruritus, mild diarrhea, and subjective chills. On physical examination, there were diffuse erythematous plaques studded with 1–2‐mm pustules on the upper extremities, chest, back, abdomen, and upper thighs (Fig. 1a–c). The pustules were distributed diffusely throughout the plaques with no obvious circinate pattern.

(a) Diffuse erythematous plaques on the abdomen and proximal upper thighs. (b) Abdomen showing coalescing pustules. (c) Proximal upper thigh showing clustered 1–2‐mm pustules on an erythematous plaque

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 Pustular psoriasis of pregnancy was the favored diagnosis; she was admitted for fetal and maternal monitoring. Admission medications included prednisone, 40 mg orally daily, and diphenhydramine, 50 mg intravenously, as needed for pruritus. Laboratory values on hospital admission are shown in Table 1.

Admission laboratory values with normal ranges in parentheses

White blood cell count
12.3 × 103/µL [(4.8–10.8) × 103/µL]

Erythrocyte sedimentation rate
45 mm/h (0–20 mm/h)

Total protein
5.7 g/dL (6–8 g/dL)

Albumin
3.3 g/dL (3.5–5.5 g/dL)

Calcium
8.2 mg/dL (8.0–10.4 mg/dL)

 A lesional punch biopsy showed a subcorneal spongiform neutrophilic pustule (Fig. 2a,b). The papillary dermis was edematous with a perivascular lymphocytic infiltrate with eosinophils. No significant acanthosis or papillomatosis of the epidermis was seen and no necrotic keratinocytes were identified. Special stains for infectious organisms were negative. In addition, bacterial and herpes simplex viral cultures taken from a pustule showed no growth.

(a) Subcorneal spongiform neutrophilic pustule and papillary dermal edema (hematoxylin and eosin; ×200). (b) Eosinophils within the lymphocytic infiltrate in the papillary dermis (hematoxylin and eosin; ×400)

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 On the second day in hospital, the patient's albumin fell to 2.6 g/dL and her serum calcium level dropped to 7.7 mg/dL (the albumin‐corrected calcium level was 8.8 mg/dL). The obstetric team elected to induce delivery to prevent fetal complications, and a healthy boy was delivered.

 During the 24 h following delivery, the patient's erythema, pustules, and pruritus improved. At the 1‐week follow‐up visit, skin examination revealed only residual scaling on the upper thighs and periumbilical skin and residual erythema on the upper back (Fig. 3a,b). She was continued on a tapered course of oral prednisone with continued resolution of the eruption.

(a) Residual scaling in the periumbilical area, 1 week after delivery. (b) Residual scaling on the proximal thighs, 1 week after delivery

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 The patient returned to the clinic several months postpartum with a new eruption. Clinically, the lesions were thought to be consistent with inverse psoriasis and topical treatment was initiated. No biopsy was performed to confirm the diagnosis.