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Blistering disorders of the Skin - NEET PG Dermatology

Apr 10, 2023

Blistering disorders of the Skin - NEET PG Dermatology

Blistering disorders are a group of skin conditions characterized by the formation of blisters, which can be a presenting feature of a wide range of dermatological diseases. These conditions include autoimmune blistering diseases, infectious disorders, drug reactions, and inherited disorders. Understanding the clinical presentation, diagnostic criteria, and management of blistering disorders is essential for dermatologists to diagnose and manage these conditions accurately.

Let’s learn more about this important dermatology topic for NEET PG exam preparation.

ENT Residency


  • Fluid filled lesions
  • < 0.5 cm called vesicles and > 0.5 cm is called bullae.


  • Autoimmune disorder
  • IgG antibodies are directed against Desmoglein (Dsg) causing intraepidermal blister. 
  • Erosion with crusting may be seen.
Pemphigus foliaceus Pemphigus vulgaris (m/c)
Defect Dsg 1 (mainly in skin)Dsg 3 (mainly in buccal mucosa) but late in disease Dsg 1 can also get involved
Separation at level of St. Granulosum St. spinosum 
Bullae Superficial (subcorneal)Deep  (suprabasal)
Easily rupturesYes No 
Involvement Skin Initially buccal mucosa and later skin
Sites Seborrheic areas (scalp, retroauricular areas, nasolabial folds, forehead, nose, Presternal, Inter scapular area, upper trunk area Buccal mucosa, scalp, trunk & extremities

Clinical signs

  • Nikolsky sign - Tangential pressure on bulla causes epidermal separation.
  • Bullae spread sign/ Asboe Hansen sign - Perpendicular pressure in bulla causes it to spread / increase in size.
  • They are positive in both but PV > PF.


  • Acanthocytes 
  • Row of tombstones appearance 

Direct Immunofluorescence (DIF)

  • Fish net like patterns due to intercellular deposition of Anti DSG Ab.


  • Steroids 
  • Cyclophosphamide
  • Rituximab (Anti- CD20)


  • lgG against BP Ag2 > BP Ag1.
  • C/F - Tense sub epidermal bullae thus do not rupture easily and the fluid gets absorbed so appears as settled bullae.
  • Histology - Sub epidermal split with eosinophilic collection. 
  • Direct Immunofluorescence (DIF) - Linear IgG & complement deposits in Basement membrane Zone.
M - Mucosal involvement
- Intraepidermal blister
N - Nikolsky sign
A - Acanthocytes
R - Row of tombstone app
PEMPHIGUS vulgaris
PEMPHIGUS vulgaris
PEMPHIGUS vulgaris
PEMPHIGUS vulgaris
PEMPHIGUS vulgaris

Direct Immunofluorescence (DIF)    






  • IgA against BP Ag 2 
  • Bimodal presentation 
  • Child (< 5 years) - Face (perioral), groin (perianal).
  • Adults (60 years) - Trunk & extremities.
  • Grouped blisters around erythematous plaques.
  • String of pearl /bead or cluster of jewel appearance.
  • DIF - Linear IgA deposits in BMZ (Basement Membrane Zone).
  • DOC  -   Dapsone

Chronic Bullous Disease Childhood 

  • Childhood variant of linear IgA disease 
Chronic Bullous Disease Childhood 


  • Gluten hypersensitivity 
  • Associations
    • Celiac disease 
    • HLA B8, DQ2, DR3
    • Anti -Endomysial Antibodies
    • Anti- Transglutaminase - 3 Antibody
  • C/F  - Extremely pruritic vesico papules, later on erosions seen over extensors
  • Histology - Papillary tip microabscesses
  • DIF        - Granular IgA deposits in dermal papilla 
  • DOC       - Dapsone 
  • TOC       - Gluten free diet
AvoidCan take
B   - BarleyRice
 - RyeMaize
O   - Oat (least amount of gluten)Ragi
W  - Wheat


  • Autoimmune 
    • C/F - Periumbilical lesions develops in females in 3rd Trimester
    • Self-limiting condition 
    • Fetal mortality is high - 30%
  • DIF - Linear C3> IgG deposits in Basement Membrane Zone
  • DOC - Steroid


  • Also known as mechanobullous disorder.
  • Occurs at the site of trauma, friction & pressure handling.

Subtypes of Epidermolysis bullosa congenita

  • EB Simplex   - defected K5/14
  • EB Junctional   - defected Laminin
  • EB Dystrophicans -  defected Collagen 7

Dermatology Related Articles:

Dermatology Related Articles:

Layers of EpidermisTypes of Sweat Glands in SkinPapulosquamous Disorders : Types and Treatment - NEET PG Dermatology
Blistering disorders of the Skin - NEET PG DermatologyAtopic Dermatitis (Eczema) - Types, Causes, Symptoms , Diagnosis and Treatment - Dermatology
Decoding Hair: Structure, Function, & Disorders
Acne Vulgaris (Grading and Treatment)Acanthosis Nigricans: Symptoms ,Causes Diagnosis And TreatmentDecoding Hair: Structure, Function, & Disorders


Feature Darier’s DiseaseHailey – Hailey’s Disease
Inheritance Autosomal Dominant Autosomal Dominant
Defect Ca2+ ATPaseCa2+ ATPase
GeneATP 2A2ATP 2C1
Site Seborrheic areas
Intertriginous areas (skin folds) like axilla, groin & inframammary folds 
Lesion Verrucous (warty lesion), greasy with sand paper feelRecurrent, flaccid, vesicular (may rupture causing erosions)
Histology Acantholysis, dyskeratosis with corps ronds, corps grainsAcantholysis, dyskeratosis with dilapidated brick wall appearance


Feature Erythema MultiformeEpidermal Necrosis
Cause Viral infection > DrugsDrugs
LesionTarget lesions/Iris lesion/ Bull’s eye lesions

Targetoid lesions
Epidermal separation as per body surface area

<10% - Steven Johnson syndrome

10 – 30% (overlap syndrome)

> 30% - TEN
Nikolsky sign Absent Present 
Mucosal involvement Absent present

Hemorrhagic crusting (SJS)

Hemorrhagic crusting (SJS)

Epidermal separation (TEN)

Epidermal separation (TEN)


  • Toxic Epidermal Necrolysis
  • Sheet like epidermal separation
  • Poor prognosis

Previous Year Questions

Q. Patient presents with oral lesions along with flaccid blisters on scalp, face, trunk and extremities, as shown in the image. Diagnosis? (AIIMS NOV 2019)

Pemphigus vulgaris
  1. Pemphigus vulgaris
  2. Pemphigus foliaceous
  3. Dermatitis herpetiformis
  4. Bullous pemphigoid

Q. Sub epidermal blisters with neutrophils, treatment of choice? (INICET Nov 2020)

  1. Rituximab
  2. Dapsone
  3. Cyclosporine
  4. Azathioprine

Q. A 10-year-old child comes with erosions and blisters on trauma prone areas. There is a history of death of a sibling after 10 days with similar illness. The most probable diagnosis is?  (AIIMS JUNE 2020)

  1. Epidermolysis bullosa
  2. Pemphigus 
  3. Congenital syphilis
  4. Chronic bullous disease of childhood

Q. Erythema multiforme is seen in? (NEET PG 2019)

  1. Celiac disease
  2. ITP
  3. Antimalarials
  4. Leukemia

Q. Arrange superficial to deep blister disease?    (AIIMS MAY 2019)

  1. Pemphigus vulgaris
  2. Linear IgA
  3. Bullous pemphigoid
  4. Epi. Dystrophica

Ans - A>C>B>D

Q. A patient with known case of T.B has been taking multiple medications and now he has presented with the given image, what is the most appropriate diagnosis? (FMGE dec 2020)

  1. Fixed drug eruption
  2. TEN
  3. SJS
  4. Scrofuloderma

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