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Indiuidual Diseases

Varicella/zoster virusa,e

Herpes simplex virusa,e

Enteroviruses, e.g.,

Hand-foot –and –mouth


Staphylococcal scalded-skin


Bullous impetigoa

  1. Subcorneal Pustular Dermatosis
    1. A chronic, benign, relapsing, pustular eruption with unknown aetiology. Female is more commonly affected than male. The peak incidence occurring at the age of 40-50. The eruption occurs mainly in the groins, axillae, submammary areas and the flexor aspect of the limbs.
    2. The face is never affected, nor are the mucous membranes.
    3. Lesions usually start off as intact pustules which dry up within a few days, forming crusts or scales.
    4. Eruption tends to group together to form clusters with advancing edge.

Differential diagnosis:

Pustular psoriasis



Skin biopsy shows the presence of subcorneal pustules.


Dapsone: Treatment of choice (50-100 mg/day)
Oral Steroid: less effective as compared with dapsone

  1. Miliaria Crystallina
    1. This condition occurs in hot and humid climate or in fever when babies are wearing too many clothes. It leads to blockage of the sweat ducts. Clinically, numerous monomorphic clear vesicles without surrounding erythema are seen on the skin, usually the trunk.
    2. Typically the skin remains dry.
    3. The disease is self-limiting. Calamine lotion can be prescribed.
    4. Prevention is by avoiding prolonged hot, humid environment and overclothing.
  2. Pompholyx
    1. A distinct pattern of acute dermatitis as characterized by acute onset of multiple itchy vesicles +/- bullae on palms and soles. Vesicles seldom rupture because of the thick stratum corneum.
    2. Usually, the cause is unknown but occasionally may be secondary to severe tinea infection or contact dermatitis occurring in other part of the body.
    3. Treatment: Requires potent topical steroid (e.g. 0.025% fluocinolone). Oral antibiotics (e.g. erythromycin) is indicated if there is evidence of secondary bacterial infection. In very
  1. Pemphigus Vulgaris
    1. Introduction
      A potentially life-threatening skin condition.
      The disease occurs worldwide.
      The peak incidence is between 4th-6th decade.
    2. Pathogenesis
      An autoimmune disease due to binding of circulating antibodies to the epidermal intercellular substance which is desmoglein. The binding leads to acantholysis i.e. loss of intercellular adhesion.
      It presents as blisters involoving the skin including mucosae (i.e. oral mucosa, conjunctiva).
      Intact blister is flaccid in nature and is easily ruptured. Ruptured bullae lead to the formation of erosions. Nikolsky's sign (i.e. rubbing normal skin causes new lesion to form) is characteristic.
      Eruption tends to develop on the trunk and the face with sparing of the extremities (centripetal distribution). Involvement of the oral mucosa gives rise to painful ulcers.
    3. Investigation
      1. Skin biopsy for histology
        This is done to confirm the diagnosis. In order to see the diagnostic features, new, rather than old lesion should be chosen for biopsy. Classically, one should find suprabasal blister with acantholysis in histology. (ROW OF TOMBSTONES )
      2. Skin biopsy for Direct Immunofluorescence (IMF)
        Perilesional skin shows the presence of intercellular IgG/C3 deposition within the epidermis.
      3. Indirect Immunofluorescence (Serology)
        Serum from the patient allows the titre of the circulating anti-intercellular antibody to be measured. The titre correlates with the disease activity and is a good parameter for monitoring the disease progress. A more than twofold increase in titre is an indication of relapse.
      4. Tzanck test
        A cytology method revealing the characteristic acantholytic cells. It provides an instant diagnosis.
        Potentially lethal disease. Hospitalization is often required for close monitoring of disease progress. Hospitalization is particularly indicated if any one of the following conditions which signifies severe involvement occurs:
        1. Extensive cutaneous involvement
        2. Systemic upset
        3. Mucosal involvement other than oral cavity
        4. High indirect immunofluorescence (IMF) titre.
    4. Systemic Treatment
      1. Oral Steroid
        1. Prednisolone is the drug of choice.
        2. DCP (Dexamethasone cyclophosphamide pulse)
      2. Steroid-sparing Agents
        Since a relatively high dose of prednisolone is usually required to control the disease, in order to prevent the long term side effects of oral steroid (e.g. opportunistic infections, osteoporosis), an immunosuppressant can be added for its steroid sparing effect. Commonly used immunosuppressants are:
        1. Azathioprine (2-3 mg/kg/day)
        2. Cyclophosphamide
        3. Methotrexate
          The major side effects of azathioprine and methotrexate are marrow suppression and hepatotoxicity. Cyclophosphamide may give rise to haemorrhagic cystitis, infertility as well as marrow suppression.
    5. Treatment of recalcitrant cases
      1. Plasmaphaeresis
      2. Pulse Methylprednisolone Therapy
      3. Cyclosporin A
      4. Dapsone
      5. Tetracycline/minocycline + niacinamide
      6. Gold
      7. Chlorambucil
      8. Biological – e.g. Rituximab.

Fig: PV- cutaneous and oral lesions

PF- cutaneous lesion

  1. Pemphigus Foliaceus is a less severe disease in which the blister is subcorneal. Target antigen is demoglein 1. No mucous membrane lesion is seen.
    1. Pemphigus erythematosus may be a localized variant of pemphigus foliaceus presenting with superficial blisters, erosions, and crusting and oozing over the scalp and face in a seborrheic dermatitis-like rash or often simulating the butterfly rash of systemic lupus erythematosus.
    2. Mucous membrane involvement is unusual in pemphigus foliaceus and pemphigus erythematosus
    3. lower doses of systemic steroids generally control these conditions. Immunofluorescent studies on skin from the edge of lesions reveal immunoglobulin and/or C3 in the intercellular areas of the upper portions of the epidermis.
  2. Familial Benign Pemphigus, Or Hailey-Hailey Disease, is a dominantly inherited disorder with suprabasal cell acantholysis; bullae arise on erythematous skin in the flexural areas (neck, axillae, groin). Warm weather and superficial bacterial infections cause flares. Spontaneous exacerbations and remissions continue for years. DIF is always negative.
    1. Familial benign pemphigus differs from other forms of pemphigus in its genetic pattern, absence of mouth lesions, benign course, and absence of intercellular antibodies.
    2. Histopathology- Dilapidated Brick Wall
      Antibiotics, both topical and systemic, may improve acute flares of the disease. When chronic vegetating lesions are present, surgical removal with skin grafting may be useful.
  3. Bullous Pemphigoid
    1. Introduction
      It is about 2 times more common than pemphigus vulgaris. Usually occurs in old age (i.e. >60). It is present worldwide and affects male to female equally.
    2. Pathogenesis
      Production of autoantibody reacting with basement membrane zone which in turns leads to separation of epidermis from the dermis. The target sites are major (BP- 230) & minor bullous (BP – 180) pemphigoid antigens which are lying in the hemidesmosomes.
    3. Clinical Features
      Early lesions in form of urticarial plaques may precede bullae. Presents as large tense blisters at lower abdomen, inner thighs, groin, axilla and flexures. Mucosal lesions are less common and often less severe than Pemphigus Vulgaris.
    4. Investigations
      1. Skin biopsy for histology
        Fresh lesion often demonstrates subepidermal blisters with mixed dermal infiltrates, especially eosinophils.
      2. Skin biopsy for Direct Immunofluorescence (IMF)
        Direct IMF of perilesional skin shows linear deposition of IgG +/- C3 at dermal-epidermal junction (Basement membrane zone)
      3. Indirect Immunofluorescence (Serology)
        Circulating IgG or C3 to basement membrane zone can be detected in 75% of patients. The serology titre does NOT correlate with disease activity. Therefore, this test is seldom performed.  
    5. Management
      Rough indication of severity
      1. Mild: < 20 lesions
      2. Moderate: 20-40 lesions
      3. Severe: > 40 lesions
        If severe, patient needs hospitalization.

Fig: BP- Large tense bullae

Fig: DH-Pattern of distribution

  1. Drug Treatment:
    1. Localized and mild case: Potent topical steroid (e.g. Clobetasol propionate) alone may control the disease.
    2. Generalized disease: Oral steroid The dosage of prednisolone required for controlling the disease is usually less than that of pemphigus vulgaris.  One can start off with 40-60 mg prednisolone daily. When the disease is under control, gradually tails it down to maintenance dose.
  2. Recalcitrant Cases:
    1. Adjuvant Immunosuppressant: e.g. azathioprine, cyclophosphamide, methotrexate, chlorambucil. Bullous pemphigoid is more commonly found in old age. These patients are more prone to the side effects of these drugs. Long term use of chlorambucil is not recommended because of the potential danger of developing acute myeloid leukaemia. Regular monitoring of CBP and LFT are needed.
    2. Tetracycline 500 mg qid/minocycline 100 mg bd + niacinamide 500 mg tds
      Pulse Methylprednisolone Therapy
      Cyclosporin A
  1. Linear IgA Disease
    1. Introduction
      A rare blistering disorder as characterized by linear IgA deposition in basement membrane zone.
    2. Clinical Features
      1. It has 2 subtypes:
        1. Adult type (around 60)
        2. Childhood type (average onset around age of 5)
      2. Cutaneous Lesions:
        1. Adult type: mainly affects trunk, face, perineum, hands and feet
        2. Childhood type: perioral region and perineum are common sites
          Blisters typically occur in clusters. (Ring of Pearls).
      3. Mucosal Lesions:
        Besides cutaneous lesions, half (70%) of the patients have oral or even ocular involvement as well.

        1. Skin biopsy for histology
          In majority of the cases, the picture resembles Dermatitis Herpetiformis. Occasionally, some may simulate Bullous Pemphigoid histologically.
        2. Direct Immunofluorescence (Direct IMF)
          Characterized by linear IgA deposition in basement membrane zone (BMZ).
        3. Indirect Immunofluorescence (Indirect IMF)
    3. Treatment
      1. Dapsone: It is the drug of choice. Response usually occurs within 48 hours. One has to be careful of dose-dependent haemolytic anaemia. Before starting dapsone, check for G-6-P-D level.
      2. Prednisolone: Used as an adjuvant therapy to dapsone or when the latter is contraindicated. Usual dosage is 5-30 mg per day.
      3. Colchicine: Used in resistant cases.
      4. Topical Treatment: Potent topical steroid can be prescribed e.g. fluocinolone 0.025%
    4. Prognosis
      1. Adult type: most patients remit within 2 years
      2. Childhood type: 50% chance of remission within 3 years
  1. Dermatitis Herpetiformis (Duhring – Broc Disease)
    1. Introduction
      An uncommon skin condition with the peak incidence around 30-40 years of age. Male is more common than female.
      1. Pathogenesis
        In western countries, the disease usually associates with coeliac disease (Gluten sensitive enteropathy).
      2. Clinical Features
        Lesions are composed of excoriated and scabbed intensely itchy papules. The sites of predilection are extensors of 4 limbs, buttocks and face. Intact vesicles are seldom seen since they are ruptured by self scratching. Lesions heal with no scarring.
    2. Differential Diagnosis
      1. Scabies: Presence of burrows, other family members are affected and sparing of the face are features suggestive of scabies.
      2. Acute eczema: Atopic eczema affects flexures more than extensors.
      3. Investigations Skin biopsy for histology: Microabscess in dermal papillae is characteristic.
      4. Direct Immunofluorescence: It shows granular IgA deposition at tips of dermal papillae.
        Screening for the presence of coeliac disease.
    3. Treatment
      1. Dapsone: It is the drug of choice. After starting the treatment, symptoms usually subside within 48 hours and rash should be cleared up within days. Side effects are haemolytic anaemia, methemoglobulinemia.
      2. Sulphapyridine / sulphamethoxypyridazine: They are used when dapsone is contraindicated.
      3. Gluten Free diet: It is useful only when the disease is associated with coeliac disease. Referring to dietician if required.
  2. Epidermolysis Bullosa
    Simplex – Intra-epidermal
    Acquisita – Sub epidermal
    1. Clinical Features
      1. This is a group of hereditary blistering disorders which are characterized by blisters and erosions resulting from trivial trauma. Blisters occur soon after birth and mainly concentrate on bony prominence of 4 limbs.
      2. An acquired form mimicking Bullous Pemphigoid known as epidermolysis bullosa acquisita (EBA) occurs in adults. Bullae tend to occur at sites of trauma.
      3. The IgG in these patients binds to the anchoring fibrils attached to the Lamina densa.
      4. EBA may be associated with underlying systemic diseases like SLE, inflammatory bowel disease, amyloidosis and internal malignancy.
    2. Investigations
      1. The diagnosis can be confirmed by skin biopsy for histopathology and electronmicroscopy. The latter is also useful in subtyping the disease.
      2. EBA can be differentiated from bullous pemphigoid by the sodium chloride split skin test and immunofluorescence on the skin specimen.
      3. In EBA, the blister occurs below the split, whereas, the blister occurs on the roof of the split in bullous pemphigoid.
    3. Treatment
      For the hereditary EB, no effective treatment is available at present. Antenatal diagnosis and genetic counselling can be offered. Systemic steroid can be useful in EBA.



In congenital dystrophic epidermolysis bullosa defect is seen in? (AIIMS Nov 08)
A. Laminin 4
B. Collagen type 7
C. Collagen 4
D. Collagen 3


Ans. B. Collagen type 7

  1. Herpes Gestationis, is a rare autoimmune condition that occurs during pregnancy and the postpartum period. It is not associated with herpesvirus infection.
    1. The blisters develop most often during the second and third trimesters and subside a few weeks post partum.
    2. Patients may experience transient flares or recurrences with each menstrual period or following the use of oral contraceptives.
    3. Recurs with subsequent pregnancies. Pruritic condition with numerous tense vesicles arising on both normal-appearing and erythematous areas of skin. Arcuate and polycyclic red plaques are seen with peripheral blistering. The lesions first appear on the abdomen around the umbilicus and then spread to involve the entire integument.
    4. Skin biopsy findings are indistinguishable from those of bullous pemphigoid by light microscopy.examination of perilesional skin by direct immunofluorescence reveals C3 and less often an IgG linear band just below the epidermis. associated fetal mortality rate as high as 30%, and also an increased rate of premature live births.
    5. Patients may require oral prednisone (20 to 60 mg/day) throughout pregnancy with intermittent tapering.
Disease Immunofluorescence finding
•  Pemphigus vulgaris
•  Bullous pemphigoid
•  Dermatitis herpetiformis
•  Linear IgA disease (chronic bullous disease of childhood)
•  Epidermolysis bullosa acquisita
•  Intercellular IgG in epidermis in fish-net pattern
•  C3 and IgG linear band at dermo-epidermal junction (Basement membrane)
•  IgA, granular band at dermal papillary tip along Basement membrane (Dermo-epidermal junction)
•  Linear band of IgA at dermal papillary tip along basement membrane
•  IgG and C3, linear band at dermo-epidermal junction
Direct immunofluorescence of blistering disorders
Positive Negative
•  Pemphigus (p. Vulgaris, P. Foliaceous)
•  Bullous pemphigoid
•  Cicatricial pemphigoid
•  Dermatitis herpetiformis
•  Linear IgA disease
•  Chronic bullous disease of childhood
•  Epidermolysis bull os a acquisita
•  Pemphigoid gestationis
•  Bullous erythematosus (bullous SLE)
•  Erythema multiforme ( occasionally positive)
•  Hailey-Hailey disease (chronic benign familial pemphigoid)
•  Darrier disease
•  Transient acantholytic dermatosis (Grover's disease)
•  Impetigo cantagiosa
•  Staphylococcal Scalded skin syndrome
•  HSV and VZV infection
•  Subcomeal pustular dermatosis (Sneddan wilkinson disease)
•  Porphyria cutanea tarda
•  Bullosis diabeticorum
Pemphigus foliaceous is similar to P. vulgaris except
  1. P. foliaceous presents with shallow erosions, associated with erythema & scales. Blisters are transient.
  2. Mucosal involvement is rare
  3. Distribution is seborrheic (scalp, central face, chest, upper back)
  4. Blister is superficial (subcorneal)
  5. Antibodies to desmoglein 1 (In P. vulgaris antibodies to both desmoglein 3 & 1 are present)
Immuno pathological appearance of vesicobullous disorders
  1. Bullous pemphigoid Linear band of IgG or C 3 in epidermal basement membrane
  2. Pemphigus vulgaris Cell surface deposits of IgG on keratinocytes
  3. Pemphigus foliaceous Cell surface deposits of IgG on keratinocytes
  4. Pemphigoid gestationis Linear band of C3 in epidermal basement membrane zone
  5. Dermatitis herpetiformis Granular deposits of IgA in dermal papillae
  6. Chronic bullous disease of childhood IgA deposits along the dermoepidermal junction
  7. Linear IgA dermatosis of adults Linear deposits of IgA at dermoepidermal junction
Direct immunofluorescence
Disease Immunofluorescence finding

Pemphigus vulgaris
Bullous pemphigoid

Dermatitis herpetiformis
Linear IgA disease
Epidermolysis bullosa acquisita

Intercellular IgG ill epidermis in fish-net pattern.
C3 & IgG linear band at dermo-epidermal junction (Basement membrane)
IgA, granular band at dermal papillary tip along basement membrane (Dermo-epidermal junction)
Linear band of IgA at dermal papillary tip along basement membrane
IgG & C3, linear band at dermo-epidermal junction.

Tzank smear findings in bullous disorders

Disorders Findings
•  Pemphigus
•  Bullous pemphigoid
•  Varicella-zoster infection
•  Herpes simplex infection
•  Toxic epidermal necrolysis
Predominantly eosinophils
Multinucleated giant cells
Multinucleated giant cells
Necrotic cells



Bullous Diseases




Pemphigus (all forms)

Deposits of IgG in intercellular areas between keratinocytes

Suprabasilar in pemphigus vulgaris; substratum corneum in pemphigus foliaceus

IgG antibodies to intracellular areas of keratinocytes in 95% of patients

Bullous pemphigoid

IgG and/or complement (C) in BMZ


IgG Ab to BMZ in 70%

Cicatricial pemphigoid

IgG and/or C in BMZ


IgG antibodies BMZ in 10%

Herpes gestationis

Complement in BMZ--occasionally IgG

Subepidermal--sub-basal cell--above lamina densa

IgG antibodies BMZ in 20% (HG factor in 25%)

Dermatitis herpetiformis

IgA in dermal papillae (granular deposits)

Subepidermal in dermal papillae--papillar dermal microabscesses

No circulating antibodies

Epidermolysis bullosa acquisita

IgG, C3 in BMZ


Frequent IgG autoantibodies

Linear IgA bullous dermatosis in childhood

IgA and complement in linear deposition in BMZ


No circulating antibodies

Connective Tissue Diseases




Bullous Systemic LE

IgG, IgM, and complement in BMZ in involved and normal skin--linear homogenous


Circulating antibodies to BMZ; ANA found in 90%

Discoid LE

IgG, other Ig, and C in lesional skin at BMZ


No circulating antibodies to BMZ, ANA titers normal

Systemic LE

IgG band at BMZ in normal skin (over 90% in sun-exposed areas)


Elevated ANA titers

Systemic sclerosis

Nucleolar IgG

Epidermal thinning and increased dermal collagen

ANA, speckled, 85%, centromere + in CREST syndrome


IgG/IgM in BMZ in some patients; nuclear IgG in epidermis


Speckled ANA and ENA (extractable nuclear antigens)




ANA often normal range

ANA = antinuclear antibody; BMZ = basement membrane zone; LE = lupus erythematosus; MCTD = mixed connective tissue disease.

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