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/NExT exam preparation.

BLISTERS 

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

PEMPHIGUS 

• 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 ruptures	Yes	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.

Histology 

• Acanthocytes 
• Row of tombstones appearance 

Direct Immunofluorescence (DIF)

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

Treatment 

• Steroids 
• Cyclophosphamide
• Rituximab (Anti- CD20)

BULLOUS PEMPHIGOID

• 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.

Pneumonic	PEMPHIGUS	PEMPHIGOID
M - Mucosal involvement I  - Intraepidermal blister N - Nikolsky sign A - Acanthocytes R - Row of tombstone app	+	-

Direct Immunofluorescence (DIF)    

Pemphigus

Pemphigoid 

LINEAR IgA DISEASE 

• 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 

DERMATITIS HERPETIFORMIS

• 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

Avoid	Can take
B   - Barley	Rice
R   - Rye	Maize
O   - Oat (least amount of gluten)	Ragi
W  - Wheat

HERPES GESTATIONIS

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

EPIDERMOLYSIS BULLOSA

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

Types
Congenita	Acquisita
Congenital	Acquired
Early	Late
Common	Rare
Genetic	Immunobullous

Subtypes of Epidermolysis bullosa congenita

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

Dermatology Related Articles:

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DARIER’S DISEASE AND HAILEY-HAILEY’S DISEASE 

Feature	Darier’s Disease	Hailey – Hailey’s Disease
Inheritance	Autosomal Dominant	Autosomal Dominant
Defect	Ca2+ ATPase	Ca2+ ATPase
Gene	ATP 2A2	ATP 2C1
Site	Seborrheic areas	Intertriginous areas (skin folds) like axilla, groin & inframammary folds
Lesion	Verrucous (warty lesion), greasy with sand paper feel	Recurrent, flaccid, vesicular (may rupture causing erosions)
Histology	Acantholysis, dyskeratosis with corps ronds, corps grains	Acantholysis, dyskeratosis with dilapidated brick wall appearance

ERYTHEMA MULTIFORME AND EPIDERMAL NECROSIS 

Feature	Erythema Multiforme	Epidermal Necrosis
Cause	Viral infection > Drugs	Drugs
Lesion	Target 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)

Epidermal separation (TEN)

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)

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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