Atypical bullous Henoch–Schonlein purpura – A case report

INTRODUCTION

Henoch–Schonlein purpura (HSP), commonly referred to as HSP, is an acute small-vessel leukocytoclastic vasculitis mediated by immunoglobulin A (IgA). It is the most frequently encountered form of vasculitis in paediatric patients, with an incidence rate of approximately 10 cases/100,000 annually.^[1] This condition affects multiple systems, including the skin, joints, gastrointestinal tract, kidneys and occasionally, the central nervous system. Although the precise cause is still unidentified, it is often preceded by a respiratory infection.^[2] HSP typically presents with a triad of symptoms: A rash featuring palpable purpura on the lower extremities, abdominal pain or kidney-related issues and arthritis.^[3] In most instances, the prognosis is quite favourable, with serious complications leading to long-term morbidity occurring in fewer than 2% of cases.^[4] Nonetheless, there are rare instances where HSP may exhibit bullous lesions rather than the anticipated purpura or petechiae. Although these lesions do not contribute to increased morbidity, they can be concerning due to the potential for various differential diagnoses. We present the case of a 10-year-old boy who exhibited an unusual presentation of HSP.^[5]

CASE REPORT

A 10-year-old, 2-month-old developmentally normal male child, vaccinated according to the National Immunisation Schedule, presented with vesiculobullous rashes over bilateral upper limbs and lower limbs for 9 days. It was associated with diffuse pain but no swelling of joints [Figures 1–4].

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Figure 1:

Ten-year-old male child presented with vesiculobullous lesions on the upper limb.

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Figure 2:

Vesiculobullous lesions on dorsum of the foot.

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Figure 3:

Vesiculobullous lesions on the lower limb.

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Figure 4:

Vesiculobullous lesions on the back.

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There was no history of trauma, bleeding manifestations, cough, cold, or fever. There was a history of fever for 1 day and similar lesions diagnosed as varicella 1 month ago, which subsided after 5 days without receiving any medications.

On examination, the child was conscious, afebrile with a heart rate of 110 beats/min, capillary refill time of <2 s, oxygen saturation of 98% on room air and blood pressure of 130/90 mmHg. Significant inguinal lymphadenopathy was present with bilateral pitting pedal oedema.

Multiple papulovesicular lesions, haemorrhagic vesicles and bullae and crusted lesions were present on bilateral upper and lower extremities and gluteal region with few lesions over the trunk. No lesions over palms and soles and no mucosal lesions were noted. Systemic examination was unremarkable.

A provisional diagnosis of persistent or recurrent varicella associated with secondary bacterial infection with cellulitis was made, and to rule out immunodeficiency disorder with nephritis and post-streptococcal glomerulonephritis, relevant investigations were done.

Peripheral blood smear showed a normochromic normocytic blood picture with relative neutrophilia and thrombocytosis. Erythrocyte sedimentation rate and C-reactive protein were elevated. Urine routine showed albumin 2+, sugar nil, 2–4 red blood cells (RBCs) and 6–8 pus cells with granular casts. No RBC casts were seen.

Ultrasonography (USG) of the abdomen, kidneys, ureters and bladder was normal. USG of right hip, leg and left arm showed mild subcutaneous oedema in the lower aspect of the thigh and popliteal region. C3 and C4 were within normal limits.

Tzanck smear showed squamous and inflammatory cells comprising lymphocytes and neutrophils. Antinuclear antibody was negative. Skin biopsy and direct immunofluorescence revealed leukocytoclastic vasculitis with predominant IgA deposition. The child was started on ceftriaxone and vancomycin as cellulitis was suspected.

Antihypertensives were started for hypertension. Steroids were considered after skin biopsy confirmed HSP.

DISCUSSION

HSP is a prevalent form of vasculitis found in children, with an incidence rate of 13.5–18 cases/100,000 children. According to the criteria for classification of HSP established by EULAR/PRINTO/PRES, the diagnosis includes purpura (often palpable purpura and occurring in groups) or petechiae, primarily located on the lower limbs and gluteal area, in conjunction with at least any one of the following criteria: (1) Diffuse abdominal pain; (2) arthritis or joint pain; (3) renal involvement (proteinuria or haematuria) and (4) biopsy showing leukocytoclastic vasculitis with predominant IgA deposition.

Conversely, bullous HSP is a rare phenomenon, accounting for <2% of HSP cases, particularly in paediatric patients.^[6] Diagnosing this condition can prove quite difficult. Differential diagnoses in these scenarios should consider drug-induced leukocytoclastic vasculitis, bullous pyoderma gangrenosum, pemphigus with linear IgA dermatosis, bullous pemphigoid and bullous systemic lupus erythematosus.^[7] Although the exact mechanism behind the bullous lesions remains unclear, they likely result from excessive matrix metalloproteinases or pressure-induced factors.

It is crucial to perform a biopsy on a fresh cluster of lesions, ideally within 2 days of their emergence, as older lesions may not display IgA deposition or leukocytoclastic vasculitis, potentially leading to a misdiagnosis.^[8] The primary focus of treatment is immunosuppression, given that IgA deposition and leucocyte infiltration are significant contributors to tissue damage. While research indicates that prompt corticosteroid treatment can alleviate abdominal pain and reduce the occurrence of intussusception, there have been reports of epidermal necrosis following corticosteroid use in some instances.^[9,10]

CONCLUSION

In summary, bullous HSP, being an uncommon manifestation, poses a diagnostic challenge for paediatricians. This requires emphasis on differential diagnoses, the importance of obtaining biopsies from fresh lesions and the treatment approach. Further evaluation of the benefits and risks associated with corticosteroid therapy are necessary to establish standardised treatment guidelines. Finally, a better understanding of the underlying mechanisms of these lesions could aid in delivering supportive care and preventing recurrence. Preventive measures, such as minimising skin pressure, managing pain and implementing antibiotic prophylaxis, may be advantageous for patients.