Acantholysis

Introduction

• The term acantholysis  is derived from the Greek words akantha, meaning a thorn or prickle, and lysis, i.e. loosening.
• Acantholysis is the term used to describe loss of cohesion between  keratinocytes, due to breakdown of intercellular bridges (eg- Desmosomes). This makes the normally polygonal keratinocytes  circular (Circular keratinocytes= Acantholytic cells). It results in the formation of intraepidermal clefts, vesicles and bullae.

Although acantholysis may occur at any level of the epidermis, the location of the blister is often used as a clue to the underlying disorder; for example, superficial (subcorneal) acantholysis favors pemphigus foliaceus, while acantholysis in the deeper aspects of the epidermis is more characteristic of pemphigus vulgaris

Acantholytic cell in pemphigus- Yellow arrow
(Ref: IJDVL. Seshadri et al.)

Primary Acantholysis

Acantholysis is either due to direct injury to desmosomes (eg: Pemphigus, bullous impetigo, staphylococcal scalded skin syndrome SSSS) or due to hereditary defects in their construction (eg: Darier's disease and Hailey-Hailey disease). Thus, in these diseases, acantholysis is the primary event leading to the formation of intra-epidermal cavities and hence the manifestations of the disease.  Eg: pemphigus, Darier’s disease etc 

Secondary Acantholysis

The acantholysis is secondary to alteration or damage to keratinocytes by various factors. In other words, keratinocytes are injured first followed by subsequent disintegration of desmosomes. Eg: In herpes, intraepidermal vesicle is secondary to ballooning degeneration of keratinocytes causing circular keratinocytes. Tzanck cells are multinucleated giant cells seen after fusion of individual acantholytic cells and is characteristically seen in herpes.

MCQs

1) A middle aged female presents with flaccid bullae in skin and oral erosions. Histopathology shows intra-epidermal acantholytic blisters. The most likely diagnosis is (PGI 05)

a) Pemphigus vulgaris

b) Bullous pemphigoid

c) Dermatitis herpetiformis

d) Epidermolysis bullosa

e) Pemphigus foliaceous

Ans: a

2) A female presents with persistent painful oral erosions with acantholytic cells. Most likely diagnosis (AI 08)

a) Dermatitis herpetiformis

b) Bullous pemphigoid

c) Pemphigus vulgaris

d) Epidermolysis bullosa

Ans: c

3) Acantholysis is seen in (PGI 99)

a) Bullous pemphigoid

b) Dermatitis herpetiformis

c) Hailey-Hailey disease

d) Darier’s disease

e) Pemphigus vulgaris

Ans: c.d.e

4) Acantholysis is seen in (AI 95)

a) Epidermis

b) Dermis

c) Dermoepidermal junction

d) Subcutaneous tissue

Ans: a

5) Acantholysis is due to destruction of (AIIMS 97)

a) Epidermis

b) Dermis

c) Basement membrane

d) Intercellular susbstance

Ans: d

6) Acantholytic cells are (SGPGI 01)

a) Epidermis cells

b) Plasma cells

c) Keratinocytes

d) Giant cells

Ans: c

7) Acantholytic cells are (PGI 96)

a) Cells with hyperchromatic nuclei and perinuclear halo

b) Cells with hypochromatic nuclei and perinuclear halo

c) Multinucleate cells

d) None

Ans: a

8) A 50 year old man with flaccid bullae and oral ulcers. Smear from skin lesions would show (AI 96)

a) Tzanck cells

b) Acantholytic cells

c) Necrosis

d) Koilocytes

Ans:b

Air Borne contact dermatitis (ABCD)

Air Borne contact dermatitis (ABCD)

Introduction

• Parthenium hysterophorus and less commonly by other plants is one of the most intractable problems in dermatology in India

• ABCD is a diagnosis that encompasses all photodermatoses predominantly of exposed parts of body, which are caused by substances released by plants which when released into the air, settle on the exposed skin and acted upon by UV light to cause disease.

• In India, parthenium is also known as "Congress grass" or "Congress weed," which refers to the US congress (who allocated the shipment for Pune, India)

• It is caused by airborne dry and friable plant particles including trichomes, and the most important allergens responsible for allergic contact dermatitis are sesquiterpene lactones (SQL)

Pathology

• Combined type IV and type I hypersensitivity to parthenium has been postulated. 

• It  is an immuno-inflammatory disease, which upon contact sensitization by parthenium antigen propagates as a cell-mediated hypersensitivity immune response with early sensitization phase and a subsequent elicitation phase, if antigen exposure persists.

 

Allergens in Parthenium dermatitis

• The most important allergens responsible for allergic contact dermatitis is sesquiterpene lactones (SQL)

• It is present in the leaf, stem, flower and pollen, but the highest concentrations of SQLs are present in the small glandular hairs (trichomes) present on the undersurface of the leaves and stem

Presentation

• Most of the airborne contact dermatitis starts from the eyelids, suggesting that airborne allergens initially lodge there because of the skin folds and cause dermatitis, later affects the face, especially the eyelids and/or neck, V of the chest

• A seasonal variation is initially observed with the dermatitis flaring in the summers corresponding to the growing season and disappearing in winters.

• Repeated exposures over many years may result in widespread, extensive, and eventually chronic lichenified dermatitis that may persist throughout the year.

• The involvement of both light-exposed and protected areas helps to differentiate ABCD from only sun induced eruptions ( photodermatitis) 

  Thickened lichenified skin (above)

Involvement of face, v of the neck

lichenified papules on dorsum of hand

Diagnosis

Patch testing with plant allergen is the simplest way of confirming parthenium contact allergy. 

• Photopatch test positive (In photopatch test, parthenium area is irradiated with UV light)= If redness is seen it indicates Parthenium + Sun dermatitis (Phytophotodermatitis)

look at redness on position no.2 on both sides

Treatment

Systemically, In India- Azathioprine is the commonest drug prescribed after initial steroid therapy, especially for chronic therapy in these usually long term diseases

MCQ

A 55 year old farmer with diabetes and hypertension gets 

air borne contact dermatitis. The drug of choice is

a) Corticosteroids

b) Thalidomide

c) Azathioprine

d) Cyclosporine

Ans: C

Nevus of Ota

(ref: DermQuest)

Nevus of Ota 

Introduction

• Nevus of Ota (Oculodermal melanocytosis) is a dermal melanocytic hamartoma that presents in childhood or at adolescence as bluish/slate gray hyperpigmentation along the first or second branch of trigeminal nerve. The pigmentation progressively increases in size and color till puberty

• Clinically, nevus of Ota presents as a blue or gray patch on the face and is within the distribution of the ophthalmic and maxillary branches of the trigeminal nerve. The nevus can be unilateral or bilateral, and, in addition to skin, it may involve ocular and oral mucosal surfaces

Pathology

• Nevus of Ota and other dermal melanocytic disorders, such as nevus of Ito, blue nevus, and mongolian spots, may represent melanocytes that have not migrated completely from the neural crest to the epidermis during the embryonic stage

Yellow arrow- Melanin and melanocytes in the dermis  (ref:IJDVL)

Presentation

Condition	Onset	Appearance	Location	Histology
Nevi of Ota and Ito	Birth/ early adolescence	Blue or gray speckled coalescing macules or patches	·         For nevus of Ota-on forehead, temple, zygomatic, or periorbital areas; ·         For nevus of Ito- the shoulder and upper arm areas	Increased dermal melanocytes
Mongolian spot	Birth	Poorly demarcated large blue-to-gray patches that tend to spontaneously resolve by age 3-6 y	Most frequently on lumbosacral areas, buttocks	Increased dermal melanocytes
Blue nevus	Congenital or acquired	Blue papules or plaques	Anywhere on skin	Increased dermal melanocytes
Melasma	Acquired; may be associated with pregnancy and other estrogen excess stages	Well-to-poorly demarcated and irregularly outlined brown patches	Maxillary and zygomatic areas on face	No increase in dermal melanocytes, presence of melanophages

Ref: Medscape

Note: For photos of Melasma and Mongolian Spots- refer to Earlier Post on " How to Decide Level of Melanin in an MCQ' posted in Feb)

Treatment

• Laser surgery is the current treatment of choice for nevi of Ota and Ito. Mongolian spot is self resolving. Q-switched lasers are advised.

Improvement post Q-Switched Laser (Ref: Kar HK, et al.  IJDVL 2011)

DOC of Bacterial STDs

Drug of choice for Bacterial STDs

Disease	Treatment	Recommending authority
Early syphilis- First 2 years (Primary/Secondary/Early latent)	Inj. Benzathine Penicillin 2.4 MU im single dose	CDC
Late syphilis- After 2 years (Late latent/Tertiary except neurosyphilis)	Inj. Benzathine Penicillin 2.4 MU im three doses at weekly intervals	CDC
Neurosyphilis	Inj. Crystalline aqueous penicillin 3-4 MU 4 hourly for 14 days	CDC
Chancroid	Tab Azithromycin 1gm single dose	WHO/ CDC/ NACO/ CEG
LGV	Doxycycline 100 mg BD for 21 days	WHO/CDC
Donovanosis	Preferred: Doxy 100 mg BD at least 3 weeks for until lesions heal Alternative: Tab Azithromycin 1 gm/week at least 3 weeks, but preferable till ulcer heals	CDC
	Tab Azithromycin 1 gm stat followed by 500 mg OD till ulcer heals  or Doxy 100 mg BD at least 3 weeks for until lesions heal	WHO
Bacterial vaginosis (Note it is not an STD)	Tab Metronidazole 400 mg BD for 7 days (preferred) Alternatives: Tab Metro 2gm single dose of Tab Tinidazole 2 gm single dose	CDC
Gonorrhea	Tab Cefixime 400 mg single dose or  Inj. Ceftriaxone 250 mg im stat	CDC/WHO/IUSTI