Bullous scabies: a case report and review of the literature.

BACKGROUND: Scabies is a common parasitic infection caused by the mite Sarcoptes Scabiei. About 300 million cases of scabies are reported annually. Scabies usually presents clinically with an erythematous excoriated papulovesicular rash, burrows, nodules and hyperkeratotic lesions in specific body areas. A rare presentation of scabies is the bullous pemphigoid-like bullous scabies. So far, to the best of our knowledge, only 32 cases of bullous scabies have been reported in medical literature, of which only 11 were under 60 years of age at the time of initial presentation. This is the first case of bullous scabies being reported from Pakistan. CASE PRESENTATION: Herein we discuss, with reference to the existing literature, the case of a 23-year-old Punjabi male who presented with a 3 day history of a tense, non-erythematous, non-tender bulla measuring approximately 0.5 cm x 0.8 cm on the right foot near the interdigital cleft. He was diagnosed to have bullous scabies. CONCLUSION: The diagnosis of scabies should be considered in all patients who present with tense bullous lesions accompanied by pruritus and a maculopapular rash. This is particularly relevant if these lesions do not resolve with steroid treatment. In such patients, in order to prevent a misdiagnosis of bullous pemphigoid, scrapings for Sarcoptes Scabiei mites and eggs should be taken.

A dilemma: bullous-pemphigoid-like eruption in scabies or scabies-induced bullous pemphigoid.

Several diseases may be confused with scabies. Atypical manifestations of scabies have previously been reported, including urticaria, contact dermatitis, and dermatitis herpetiformis. There are also reports of scabies mimicking bullous pemphigoid. Here we report a case of scabies in a patient with manifestation similar to bullous pemphigoid. Direct smear of the bullous lesions was performed and was positive for scabies mites. The skin biopsy specimens submitted for light microscopy and direct immunofluorescence study were considered to be compatible with bullous pemphigoid. The patient treated with single dose oral ivermectin and prednisolone. The pruritus subsided and the eruption improved dramatically in 2 weeks.

Scabies presenting with bullous pemphigoid-like lesions.

A wide range of clinical manifestations may be seen in scabies, from classic pruritic papules and burrows to secondary features such as impetigo. Bullus lesions are a less frequent. Twenty cases of scabies presenting with bullae have been reported so far in the medical literature. Differentiating this subtype of scabies from the immunobullous disease bullus pemphigoid is a diagnostic challenge. A 42-year-old man was referred to our dermatology outpatient clinic with 3-month history of severe pruritus and tense blisters affecting mainly the lower trunk, arms and legs. An initial biopsy was suggestive for bullous pemphigoid. Close physical examination revealed small excoriated papules and a few burrows on borders of the hands and wrists. Skin scraping of the lesions on wrists was positive for Sarcoptes scabiei. Another biopsy specimen from a recent blister revealed subepidermal bullae with fibrin and inflammatory cells, particularly eosinophils. Direct immunofluorescence exam was negative. The patient was treated with lindane lotion followed by crotamiton cream with near complete resolution of the lesions. Scabies must be considered in patients presenting with recent onset of unexplained pruritic bullous lesions. Biopsy and immunofluorescence studies together with skin scrapings for Sarcoptes scabiei could help to differentiate these cases from bullous pemphigoid. Antiscabietic treatment results in resolution of bullous lesions in the affected patients.

A case of crusted scabies with a bullous pemphigoid-like eruption and nail involvement.

We report a case of a 71-year-old man infected at a nursing home who developed a bullous pemphigoid-like eruption with nail involvement. He was diagnosed by his family doctor as suffering from eczema and was treated with topical corticosteroids, then blisters started appearing. He was next diagnosed as suffering from bullous pemphigoid and treated with oral prednisolone, which worsened his condition. He was finally diagnosed as having crusted scabies with bullous pemphigoid-like eruptions and nail involvement at our clinic. He was then prescribed oral ivermectin (two doses of 12 mg ivermectin with a 1-week interval) and topical lindane (1%gamma-BHC in petrolatum) for scabies with 5% salicylic acid in plastibase as an additional treatment for the crusted lesions on his soles. He showed remarkable improvement in 2 weeks, and his nails showed complete recovery after 7 weeks of occlusive dressing treatment with 1%gamma-BHC. One and a half years later, the patient showed no sign of a recurrence of scabies. The histology of a blister taken from this patient was similar to that of bullous pemphigoid. Direct immunofluorescence showed immunoglobulin (Ig)G and C3 deposition at the dermoepidermal junction similar to that of bullous pemphigoid, but indirect immunofluorescence was negative. The bullous symptoms of this patient were considered to be due to the scabies, because the patient recovered completely after receiving treatment for scabies. Indirect immunofluorescent study is important to distinguish between scabies with blister formation and true bullous pemphigoid.