| Bullous impetigo |
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Staphylococcus aureus:Exfoliative toxin A and B cleave desmoglein-1 → disruption of keratinocyte attachments
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- Vesicles that grow to form large, flaccid bullae, which go on to rupture and form thin, brown crusts
- Affects the trunk and upper extremities
- Severe cases: systemic signs (e.g., fever, malaise, weakness)
- Negative Nikolsky sign
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- Wound cleansing with antibacterial washes
- First-line
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First-generation cephalosporins (e.g., cephalexin)
- Dicloxacilin
- Alternative
- Amoxicilin-clavulanate
- Macrolides
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MRSA infection
- Clindamycin
- Trimethoprim-sulfamethoxazole
- Doxycycline
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| Staphylococcal scalded skin syndrome (SSSS) |
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- Initially: fever and diffuse or localized erythema that begins periorally
- After 24–48 hours
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Flaccid, easily ruptured blisters that break to reveal moist, red skin beneath (resembles scalding)
- No mucosal involvement
- Positive Nikolsky sign
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- Hospitalization
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IV antibiotics
- Nafcillin, oxacillin
- Vancomycin (in settings with high MRSA prevalence)
- NSAIDs
- Supportive case (esp. fluid resuscitation)
- Emollients
- Dressing of areas where skin has sloughed off
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| Stevens-Johnson syndrome (SJS)/toxic epidermal necrolysis (TEN) |
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Adverse drug reaction (most common)
- Sulfasalazine
- Oxicam NSAIDs
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Antiepileptics (e.g., phenytoin, phenobarbital)
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Antibiotics: sulfonamides (e.g., TMP/SMX), aminopenicillins
- Infections: mycoplasma pneumonia
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Prodromal phase (1–3 weeks after trigger exposure/infection)
- High fever, malaise, sore throat, myalgia, and/or arthralgia
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Mucocutaneous lesions (1–3 days after prodromal phase)
- Cutaneous
- Painful, erythematous/purpuric macules
- May have a targetoid appearance
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Bullae and/or vesicles
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Mucosal
- Oropharyngeal: stomatitis, mucositis, pharyngeal involvement
- Ocular: severe conjunctivitis, corneal ulcers, anterior uveitis
- Urogenital: urethritis, ulcerative vaginitis, vulvar bullae
- Positive Nikolsky sign
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- Discontinue causative drug
- Supportive therapy and wound management
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Antibiotic therapy (in infection/sepsis)
- Regular dermatological, ophthalmological, and urological/gynecological evaluation
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| Epidermolysis bullosa acquisita |
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- Autoantibodies against type VII collagen
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- Subepidermal blistering
- Noninflammatory form (most common)
- Tense vesicles and blisters on extensor surfaces (e.g., hands, knees, knuckles)
- Inflammatory form
- Tense vesicles and bullae on areas such as the trunk and skin folds)
- Negative Nikolsky sign
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- Systemic steroids
- Immunosuppressants
- Avoid skin trauma
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| Bullous pemphigoid |
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- Type II hypersensitivity reaction
- Antihemidesmosome antibodies (IgG)
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Prodromal stage: urticarial lesions
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Large, tense, subepidermal blisters on normal, erythematous, or erosive skin weeks to months after prodromal stage
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Intensely pruritic, possibly hemorrhagic, lesions, heal without scar formation
- Distributed on palms, soles, lower legs, groin, and axillae
- Oral involvement is rare
- Negative Nikolsky sign
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-
First-line: high-dose topical steroids (e.g., clobetasol, betamethasone)
- Second-line: systemic glucocorticoids and immunosuppressants (e.g., methotrexate, azathioprine)
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| Pemphigus vulgaris |
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- Type II hypersensitivity reaction
- IgG antibodies against desmoglein 3 and desmoglein 1
|
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Initially affects the oral mucosa before extending to parts of the body exposed to pressure
- Progression in stages
- First, spontaneous onset of painful flaccid, intraepidermal blisters
- Then, rupture and confluence of lesions → development of erosions and crusts → reepithelialization with hyperpigmentation but without scarring
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Pruritus is typically absent
- Positive Nikolsky sign
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- First-line: Rituximab and systemic glucocorticoids (e.g., prednisone)
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Systemic glucocorticoids plus immunosuppressive therapy (e.g., azathioprine)
- Topical treatment
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| Dermatitis herpetiformis |
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- Most likely genetic predisposition to autoimmune reaction
- Associated with celiac disease and sensitivity to potassium iodide (e.g., contrast medium)
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Tense, grouped subepidermal vesicles, papules, and/or bullae (herpetiform appearance)
- Intensely pruritic
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Bilateral, symmetrical distribution (e.g., elbows, knees, buttocks, shoulders, scalp)
- No mucosal involvement
- Negative Nikolsky sign
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- First-line: dapsone
- Gluten-free diet
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Topical steroids to control severe pruritus
- Low-iodine diet
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