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rash_bullous

bullous / blistering rashes

introduction

  • bullous rashes are those with large fluid filled superficial cutaneous bullae

types of lesions

  • Nikolsky sign
    • applying lateral pressure to an area of normal appearing skin or mucosa causes formation of a blister
    • may be present in epidermolysis bullosa, pemphigus, mucous membrane pemphigoid, lichen planus and lupus erythematosus
  • sub-epidermal blisters
    • tense roof which often remain intact
    • eg. bullous pemphigoid, friction blister, dermatitis herpetiformis, erythema multiforme, TEN
  • intra-epidermal vesicles
  • subcorneal lesions
    • very thin roof which breaks easily
    • eg. impetigo, miliaria, SSSS

intra-oral blisters

  • viral vesicular lesions which usually present as mucosal ulcers:
  • simple blood blisters:
    • angina bullosa hemorrhagica (ABH)
      • characterized by abrupt and unprovoked presentation of blood-filled blister over the oral mucosa
      • usually middle aged persons
      • usually on soft palate
      • usually painless although may have some burning sensation and resolve within days, and may recur intermittently over many years
    • the autoimmune disorders listed below may also present with blood filled blisters
  • rare, autoimmune disorders:
    • pemphigus
    • bullous pemphigoid
    • gestational pemphigoid
    • cicatrical pemphigoid
    • linear IgA disease

DDx of acute blistering conditions

DDx of chronic blistering diseases

  • bullous pemphigoid
    • an uncommon immunobullous disease where antibodies are found along the basement membrane that lies between the epidermis and dermis on biopsy
    • usually affects middle aged or elderly persons with average age of onset of 65yrs
    • appears to affect ~7 per million people per year and may follow other chronic dermatoses such as lichen planus or psoriasis, while some drugs have been implicated as a cause (eg. non-steroidal anti-inflammatory drugs (NSAIDs), frusemide / furosemide / Lasix, captopril and antibiotics), and some cases may follow UV irradiation or radiotherapy.
    • a non-specific rash may precede blisters by several weeks or months
    • may be localised, often on trunk, limbs, esp. in skin folds
    • rarely is oral but in severe cases may involve all of skin and mucosa is involved in 10-25% of cases
    • healed blisters leave brown pigmented marks or milia but these resolve over a few months
    • various forms:
      • generalised form:
        • most common presentation with tense bullae on any part of skin esp. flexures
      • vesicular form:
        • groups of small, tense blisters, often on an erythematous or urticarial base
      • vegetative form:
        • very uncommon, plaques in intertriginous areas of the skin, such as the axillae, neck, groin, and inframammary areas
      • generalized erythroderma form
        • rare, exfoliative erythroderma which may mimic other conditions such as psoriasis, or atopic dermatitis
      • urticarial form
        • present with persistent urticarial lesions which eventually blister
      • nodular form
        • rare, blisters arising on normal-appearing or nodular lesional skin
      • acral form
        • childood form following vaccinations
        • lesions mainly on palms, soles, and face
      • infant form
        • mainly palms, soles, and face
      • non-bullous pemphigoid
        • these patients have few if any blisters
    • diagnosis
      • if classical, diagnosis may be on clinical grounds alone
      • biopsy of lesion and direct immunofluorescence staining
      • serologic indirect immunofluorescence may show circulating pemphigoid antibodies
    • untreated, it can persist for months or years, with periods of spontaneous remissions and exacerbations
    • Rx is usually needed for 1.5-5yrs and in most cases the condition resolves
    • mortality is same or perhaps up to twice that of normal patients although is mainly higher in those with other co-morbid conditions of the elderly population which may not tolerate the Rx required
  • pemphigus
    • pemphigus vulgaris
      • a rare autoimmune disease that is characterised by blisters and erosions on the skin and mucous membranes, most commonly inside the mouth
      • IgG autoantibodies bind to a protein called desmoglein-3, which is found in desmosomes in the keratinocytes near the bottom of the epidermis
      • may be provoked by sun exposure
      • mainly affects those in their 50's, esp. Jews and Indians, but may affect any race, at any age
      • 1 case per million in NZ
      • 50-70% develop oral lesions
      • other mucosal sites include conjunctiva, oesophagus, labia, vagina, cervix, penis, urethra and anus
      • lesions are painful and slow to heal
      • skin lesions are thin walled flaccid blisters which easily rupture causing painful erosions
      • diagnosis is via biopsy
      • Rx is mainly long term high dose corticosteroids which has reduced mortality from 99% to 5-15% but does not cure the condition
    • pemphigus foliaceus
      • a rare relatively benign form of pemphigus, and also mainly occurs in the 50's but unlike pemphigus vulgaris, there is little or no mucosal involvement.
      • blisters tend to form when the skin is rubbed (Nikolsky sign), and are most common on the trunk
      • autoantibodies (usually IgG) bind to desmoglein-1, which is found in desmosomes in the keratinocytes near the top of the epidermis
      • it may resolve without Rx, or just require topical corticosteroids, although severe cases may require oral doses
      • 6 sub types:
  • pemphigoid gestationis
  • cicatricial pemphigoid
    • usually elderly; severe blistering of mucosa, including eyes, genitals, resulting in scarring
    • rare, usually young adults with coeliac disease
    • very itchy papules and vesicles, esp. scalp, shoulders, buttocks, elbows and knees
  • Hailey-Hailey disease - rare, hereditary
  • epidermolysis bullosa - rare, hereditary, 10-50 cases per million births
  • epidermolysis bullosa acquisita
    • rare, 3 main forms
    • tense vesicles and bullae, and erosions primarily on trauma-prone areas such as the extensor surfaces of hands, knuckles, elbows, knees, and ankles, while blisters on mucus membranes rupture easily
    • generalized inflammatory form is not localised to trauma-prone sites
    • a mucosal variant clinically resembles mucous membrane pemphigoid and can result in significant mucosal scarring and dysfunction
  • linear IgA dermatosis (LAD)
    • rare, autoimmune, childhood (typically lower abdomen and anogenital but also, hands, feet, peri-oral and oral) and adult forms (less anogenital/perioral lesions)
    • often have ocular symptoms
  • chronic bullous dermatosis of childhood
  • dyshidrosis
  • bullous systemic lupus erythematosus (BSLE)
  • etc
rash_bullous.txt · Last modified: 2015/10/17 11:37 by gary1