Pustular Psoriasis in Pregnancy: Diagnosis, Management, Complications

(i) Diagnosis

Based on the clinical presentation of a 28-year-old female with a long history of psoriasis developing symmetrical, flexural, and grouped pustules with high-grade fever and severe constitutional symptoms in the third trimester, the most probable diagnosis is Generalized Pustular Psoriasis of Pregnancy (GPPP), also historically known as Impetigo Herpetiformis (IH).

• Key Diagnostic Features:
  • Pre-existing Psoriasis History: The patient has a long history of psoriasis, indicating a predisposition. While GPPP can arise de novo, a prior history is common.
  • Onset in Third Trimester: GPPP typically manifests in the third trimester, although it can occur earlier.
  • Clinical Morphology: Symmetrical, flexural, and grouped sterile pustules on an erythematous base are characteristic. These lesions often begin in skin folds and spread centrifugally.
  • Systemic Symptoms: High-grade fever and severe constitutional symptoms (malaise, nausea, diarrhea, arthralgias, tachycardia, delirium, seizures) are hallmark features, distinguishing it from milder dermatoses of pregnancy.
  • Laboratory Findings (Expected): Leukocytosis, elevated Erythrocyte Sedimentation Rate (ESR), increased C-reactive protein (CRP), and potentially electrolyte imbalances (e.g., hypocalcemia, hypoalbuminemia). Pustules are sterile on bacterial culture.
• Differential Diagnoses: It is crucial to differentiate GPPP from other pustular dermatoses and dermatoses of pregnancy, which include:
  • Acute Generalized Exanthematous Pustulosis (AGEP)
  • Pemphigoid Gestationis
  • Polymorphic Eruption of Pregnancy (PEP)
  • Dermatitis Herpetiformis
  • Subcorneal Pustular Dermatosis

(ii) Management of the Condition

Management of GPPP requires a multidisciplinary approach involving dermatologists, obstetricians, and neonatologists, focusing on rapid control of symptoms, maintenance of maternal homeostasis, and fetal well-being. Treatment options must carefully consider fetal safety.

A. General Measures and Supportive Care:

• Hospitalization: Essential for close monitoring of both mother and fetus due to the severe nature of the disease.
• Fluid and Electrolyte Balance: Aggressive rehydration and correction of electrolyte imbalances (especially hypocalcemia, if present) are critical.
• Nutritional Support: High-protein diet and nutritional supplements to address hypoalbuminemia and increased metabolic demands.
• Temperature Regulation: Cooling measures to manage high fever and prevent hyperthermia.
• Infection Control: Close monitoring for secondary bacterial infections, as eroded skin can be a portal of entry. Systemic antibiotics if infection is suspected.
• Pain Management: Analgesics for arthralgias and skin discomfort.
• Fetal Monitoring: Continuous fetal heart rate monitoring, regular ultrasonography to assess fetal growth and placental insufficiency.

B. Pharmacological Management:

The choice of systemic therapy is crucial, balancing efficacy for the mother with fetal safety. There are no universally accepted guidelines, but corticosteroids are often the first line.

C. Obstetric Management:

• Timing of Delivery: If maternal or fetal condition deteriorates despite optimal medical management, early delivery may be considered, as GPPP often resolves rapidly postpartum.
• Mode of Delivery: Psoriasis does not generally dictate the mode of delivery (vaginal vs. C-section), but care should be taken to avoid exacerbating skin lesions (Koebner phenomenon).

(iii) Complications

GPPP is a serious condition that can lead to significant complications for both the mother and the fetus if not effectively managed.

A. Maternal Complications:

• Systemic Illness:
  • Fever and Dehydration: High fever and extensive skin lesions can lead to significant fluid and electrolyte imbalances.
  • Erythroderma: Severe cases can progress to erythroderma, affecting the entire skin surface, leading to impaired thermoregulation and increased fluid loss.
  • Hypoalbuminemia: Due to inflammation and protein loss through the skin.
• Infections:
  • Maternal Sepsis: The compromised skin barrier and systemic inflammation increase the risk of severe bacterial infections and sepsis, which can be life-threatening.
• Cardiovascular and Renal Complications:
  • In severe, untreated cases, complications like cardiac or renal failure can occur.
• Metabolic Disturbances:
  • Hypocalcemia is a recognized association, which can lead to tetany and seizures.
• Recurrence: GPPP tends to recur in subsequent pregnancies, often with earlier onset and increased severity.

B. Fetal Complications:

• Placental Insufficiency: Systemic inflammation and maternal illness can impair placental function.
• Intrauterine Growth Restriction (IUGR): Reduced nutrient and oxygen supply to the fetus.
• Fetal Distress: Can occur due to maternal illness and placental issues.
• Premature Delivery: Increased risk of preterm birth, sometimes induced due to maternal or fetal compromise.
• Fetal Abnormalities/Malformations: While not directly caused by the disease itself, certain contraindicated medications can lead to this. Close monitoring is crucial.
• Stillbirth/Neonatal Death: The most severe fetal outcomes, particularly in poorly controlled or severe cases.