Eczemas😍

Eczemas

General Classification

• Type of dermatitis

Broadly classified into:

Exogenous Eczemas

Contact Dermatitis

Allergens and Their Sources in ACD

Parthenium Dermatitis

 

• Mnemonic:
• Wild
• Sexy → Sesquiterpene lactone (Allergen)
• Congress (Wild grass/Congress grass)
• Flying → Airborne contact dermatitis → ABCD
• Wearing joker nose → Nose spared (Nose tip sign)
• Destroy other parties → aggressive dominance and allelopathy

• Most common cause in India: Parthenium Hysterophorus.

• Allergen: SQL (Sesquiterpene lactone).

• Population: Mostly farmers and people in fields.

• Other names: Wild grass/Congress grass.

Clinical Features

• Subacute eczema is majorly seen.

• Itchy.

• Only exposed parts of the body show dermatitis.

• Major affected parts:
• Face
• Neck
• Upper part of chest
• Upper back
• Flexures

• Nose is spared - Nose tip sign.

Important Information

• Found in America, Asia, Africa, and Australia.

• Health Hazards:
• Causes allergic respiratory issues.
• Induces contact dermatitis.
• Parthenium dermatitis is airborne.
• Referred to as Airborne contact dermatitis (ABCD).
• Leads to mutagenicity in humans and cattle.

• Agricultural Impact:
• Shows allelopathy – inhibits growth of nearby crops.
• Results in significant reduction in crop yield.

• Environmental Threat:
• Exhibits aggressive dominance.
• Classified as a noxious weed in these regions.
• Poses serious threat to biodiversity.

Diagnostic Test for ACD

Patch Test for ACD

• Most effective test (IOC) for ACD

• Indications:
• Helps to identify the allergen.
• Used to rule out if it is ACD or not.

• Test chemicals are applied to the back during
• TRUE Test (Thin layer Rapid Use Epicutaneous) administration.

• Principle:
• Simulating the Elicitation phase of ACD.

• Hypersensitivity:
• Type IV Hypersensitivity reaction.

• Site: Patient's back.

• Best reading:
• Taken at 48 hours < 96 hours.
• To look for delayed reactors.

Diagnostic Test for Photoallergic Dermatitis

Photopatch Test

• Antigen patches are applied in duplicate.
• One patch is covered with opaque material.
• One side is irradiated with UVA at 48 hours.

Management

• Avoid irritants:
• Most important (treatment of choice).

• Topical steroids.

• Oral steroids.

• Azathioprine.

• Cyclosporine.

Important Information

• Retinoids are not given due to dryness
• which may lead to more irritation.

Endogenous Eczemas

Atopic Dermatitis

• Itchy, chronic, or chronically relapsing inflammatory skin condition.

• Other name: Itch that rashes / itch is a disease.

Atopic Triad:

• Personal or family history of Atopic Triad may be seen.
1. Atopic Dermatitis
2. Asthma
3. Allergic Rhinitis (Hay fever)

AD Pathogenesis

Clinical Features (3 types based on age group)

Infantile:

• > 3 months to 2 years.

• As they crawl, they come in contact with external factors.

• Locations:
• Face, scalp, trunk, diaper area,
• extensor surfaces of extremities.

Adolescent (childhood type):

• 2 to 12 years.

• Allergens deposit on the flexural folds.

• Locations:
• Antecubital fossa
• popliteal fossa
• neck, and ankles.

Adult type:

• 12 years.

• Indulge in a lot of work.

• Locations: Hands, feet, and flexural folds.

• Flexural lichenification → secondary change

 

Associated with:

• Keratosis pilaris.

• Hyperlinear palms and soles.

• White dermographism.

• Can have Dennie Morgan fold (extra skin fold in the lower eyelid).

Diagnosis

• Mainly clinical.

• Raised Ig E.

Hanifin and Rajka Criteria for Diagnosis of AD

• Raja kk chorichil
• Pruritis, Rash, Relapsing, Family h/o

Major criteria (must have three or more):

1. Pruritus.

2. Typical morphology & distribution.
• Facial/extensor involvement in infants and children.
• Flexural lichenification in adults.

3. Chronic or chronically relapsing dermatitis.

4. Personal or family history of atopy (Asthma, allergic rhinitis, atopic dermatitis).

Management of ACD

• Environmental factors: Removing triggers.

• Barrier compromised: Hydration + Moisturizers.

• Immunological factors: Giving pharmacological treatment.
• Topical corticosteroids, Topical Calcineurin inhibitors.
• Oral Corticosteroids, Cyclosporine, and Azathioprine.

• Newer drugs:
• Dupilumab: IL-4 receptor alpha antagonist (systemic).
• Apremilast: PDE-4 inhibitor (oral).
• Crisabole: PDE-4 inhibitor (topical).
• Mnemonic: I love Dupe 4
• Mnemonic: April (Apremilast) il Savala (Crisabola) arinju

Pityriasis Alba

• Pityriasis: Scaly.

• Alba: White.

• Mnemonic: Pity that u sticked multipe () white lacy () sponges (Spongiosis) on your face

Clinical Presentation

• Usually in children.

• Atopic.

• Multiple hypopigmented asymptomatic ill-defined macules and patches on the face.

• Macules are associated with mild scaling.

On Histopathology

• Spongiosis is present.

• Vs Indeterminate Hansen-endemic area:
• Solitary lesion, no scaling, not episodic.
• On Histopathology - Periappendageal infiltrate.

Treatment

• Moisturization.

• Topical corticosteroids.

• Topical calcineurin inhibitors.

Morphea

• Morphea

• Autoimmune connective tissue disorders

• NOT a part of systemic sclerosis
• Involves skin
• Contain collagen
• No visceral organ involvement

Seborrheic Dermatitis

• Present in Seborrheic area.

• Chronic inflammatory papulosquamous disease.

• Pathogenesis: Increased sebum.

• Organism: Malassezia globosa.

• Age:
• Infants:
• < 3 Months old
• due to transfer of maternal hormones.
• After puberty.

• Sites of Seborrheic Dermatitis:
• Scalp, face, chest, upper back, upper trunk.

Clinical Presentations of Seborrheic Dermatitis

• In < 3-month-old
• Infantile Seborrheic Dermatitis
• Cradle cap is seen:
• Greasy scales of the scalp,
• also seen on the face.

In adults:

• Usually dandruff.

• Inflammation with greasy scales - around nasolabial folds, eyes, and behind ears.

Management

• Topical ketoconazole shampoo.

• Topical/ oral antifungals.

• Mild Topical corticosteroids.

• Avoid oil application.

Pompholyx Eczema

• Endogenous hand eczema.

CF

• Recurrent vesicular eczema on hands and feet.
• Deep sealed itchy vesicles are seen.
• Sago grain vesicles.

• Bilaterally symmetrical.

• Relapsing - Remitting.

Treatment:

• Topical Corticosteroids

• Moisturization.

• Oral Corticosteroids

• Cyclosporine, and Azathioprine.

Asteatotic Eczema

• Asteatotic: No fat, thus the name No fat rash.

• Season: Winters or Dry seasons.

Age:

• Seen in elderly, atopics, usually lower legs.

• Due to less fat and dry skin.

• Absence of Odland bodies or lipid-coated granules.

Cracked skin

• cracked porcelain or crazy paving pattern

• dried riverbed pattern

Other names:

• Eczema craquele

• Winter eczema.

Treatment:

• Moisturize, topical steroids, antihistamines.

Lichenification (Lichen Simplex Chronicus)

• Components of Lichenification:
1. Increased skin pigmentation.
2. Increased skin markings.
3. Thickening of skin.

• Form of neurodermatitis.

• Itch scratch cycle
• Severe itching → destroys skin barrier → more itching.

• Lichenified plaques
• which are very itchy.

• On histopathology:
• Acanthosis is seen.