What causes eczema? Is dermatitis and eczema is same, before this we will study what is Eczema. A medical condition in which patches of skin become rough and inflamed which cause itching and bleeding & occasionally causes blisters.
Generally both these terms are used interchangeable so in short, YES Eczema & Dermatitis are same and it means inflammation of skin due to various allergens and on that basis there are broadly 8 types of Eczema as discussed below.
Exogenous Eczema
- Contact irritant dermatitis
Due to exposure to detergents and vegetables, seen in housewife that’s why called as housewife’s eczema.
May occur on first exposure, Memory T cells are not formed. - Contact allergic dermatitis
Due to exposure to allergens like
Nickel found in ornaments, potassium dichromate in cement, Thiorum in rubber, Cobalt chloride in tattoo dye.
Does not occur on first exposure, memory T cells are formed.
Diagnosis is done by Patch test.
A small quantity is placed in filln Chambers and small quantity of the allergen is placed over the back of the patient, if patient comes positive for allergen, it confirms the diagnosis.
Two readings are taken on day 2nd(48hrs) and day 4 (96hrs) respectively to confirm the diagnosis. - Airborne contact dermatitis
Causative agent: plant Congress grass,
Causative Allergen: sequesterpine lactone also know as Partheniumhysteroporus.
It occurs by the air carrying the Pollen of this plant and therefore this dermatitis mostly affects the exposed areas of the body like face, hand, feet.
Commonly seen in farmers and gardeners.
Patch test is positive for sequesterpine lactone.
Endogenous Eczema
1.Nummular (discoid) eczema
A stubborn, itchy rash that forms coin-shaped patches on the skin (nummular means coin in Latin). The lesions as they get older may clear in the center or become scaly and then resemble fungus (ring worm) or psoriasis.
2.Statsis Dermatitis
Due to pooling of blood, gravitational eczema.
Skin inflammation in the lower legs caused by fluid build-up.
Stasis dermatitis is caused by fluid build-up due to varicose veins, circulation issues or heart disease.
Skin discolouration of the ankles or shins, itching, thickened skin and open sores (ulcers) are symptoms.
Treatments may include compression stockings and prescription creams as well as treating the underlying condition.
3.Craddle cap/ Seborrheic dermatitis
Seen on the scalp of infants, It can also occur on oily areas of the body, such as the face, upper chest and back.
In addition to scaly patches and red skin, seborrhoeic dermatitis can cause stubborn dandruff.
Treatment involves self-care and medicated shampoos, creams and lotions. Repeated treatments may be necessary.
4.Asteatotic Eczema/Winter eczema/ eczema craquele
Due to cold and lipid deficiency, occurs when the skin becomes abnormally dry, itchy and cracked. It is often found in elderly people, though it is not uncommon for people in their 20s.
5.Atopic dermatitis
Skin Rash which is common in child, can also occur in adult. Atopic meaning allergy, Derma meaning skin and itis information. Atopic dermatitis is defined as a skin inflamation in response to allergy, more specifically it occurs as a result of the inappropriate attack by our immune system on the skin targeting the flexor surfaces like
Inside of elbow,
creases of wrists,
back of knee
& exposed skin surface.
Increased transdermal water loss
What causes eczema (Pathophysiology)
When Immune system attacks inappropriately itself it is known as hypersensitivity. There are 4 types of hypersensitivity reaction. Atopic dermatitis is a type 4 hypersensitivity reaction. Starts off with something in the environment called allergen light flower Pollen.
The Pollen travels to the slightly porous skin where it is picked up by immune cell known as antigen presenting cells since it present the antigen that is Pollen to the naive T cells which is converted into TH2 Cell. This TH2 cell activates nearby B cell to produce IgE or immunoglobulin E antibodies specific to that pollen. These IgE antibodies binds to the surface of other immune cells called mast cells, Basophils which our found in the tissue layer just below the skin. This process is known as sensitization.
Now let’s say there is another episode of exposure to pollen (2nd episode) and it makes it way into the skin tissue, now the allergen can cross link the IgE sensitized cells, resulting in degranulation and release of Pro-inflammatory molecules like histamine, Leukotriens and Proteases. The cumulative effect of these molecules is to dilate the nearby blood vessel and to become leaky there by attracting more immune cells in the area causing inflammation of the skin tissue.
Ultimately this inflammation makes the skin barrier more leaky, potentially allowing more of the allergen as well as water to escape, making skin dry & scaly. dry skin is verry itchy and hence person scratches causing more damage to the skin barrier and the itching aggravates leading to viscious itch-scratch-itch cycle.
Occasionally bacteria can invade into skin causing more inflammation.
Atopic dermatitis can worsen in the presence of allergens like cigarette smoke, mold & dust mites,
With change in weather,
With stress.
Usually causes a patch or red itchy skin that come & go. The skin may occasionally blister & peel. Over time the skin can become lichenified (leather like).
Itchiness is often worse at night probably because there is no distraction.This is when children scratch their eczema lessions.
Since it a autoimmune condition, it can’t be spread to other people. But since it affects the skin and affects appearance, there’s a lot of social stigma to it. Unfortunately many of them specially teenagers suffers from depression & social anxiety as a result.
Genetics play an important role in it’s pathogenesis. And often individuals with atopic dermatitis also suffers from Asthma, allergic rhinitis which is known as atopic triad. These illness often run in family.
Occasionally it can also be a part of some syndrome like
Hyper IgE syndrome, Autosomal Dominant (AD) form known as Job Syndrome.
Phenylketonuria, metabolic disorder that results from the buildup of Phenylalanine.
Wiskott-Aldruch syndrome, X linked recessive disease characterised by clinical triad of Eczema, thrombocytopenia & immunodeficiency.
Diagnosis
Mostly Clinical.
Diagnosis is made by Hanifin & Rajka Criteria.
Hanifin & Rajka Criteria
Consists of 4Major & 23Minor criteria.
Major Criteria
- Pruritis
- Chronic
- Family history of atopy
- Distribution of lesion: Adult – flexors, children- flexors and face, Infants- flexors, face, extensors.
Few minor criteria out of 23
- Allergic
- White demographism
- P. Alba
- Keratoconus
- Dennie Morgan fold- extra skin fold in lower eyelid
- ASSC (Ant-Sub Capsular Cataract)
- Wool intolerance
- Food intolerance
HistoloPathological Findings
Acute Phase– Spongiosis (oozing out lesions)
Chronic Phase – Acanthosis (Lichenified lesions)
Treatment
There are ways to break the cycle of allergy mediated information, dry skin, itching.
Identify & avoid triggers
Avoid overheating
Choose a soft fabric for dress material
Manage stress
For Dry skin, applying moisturizer after a warm bath before going to bed.
Itching is easily managed by keeping your nails short, trying to keep children from scratching.
Most of them resolve by following this basic skin regimen but for several cases following immune suppressants are used.
Acute Dermatitis: Corticosteroid (Topical+ systemic)
Chronic Dermatitis: Corticosteroid,Topical Tacrolimus ( calcineurin inhibitor),
Systemic- Azathioprine
Antihistamines (for itching)
Antibiotics (if infection develops)
Atopic Dermatitis: For Mild/Moderate atopic dermatitis: Crisaborol- PDE-4 inhibitor.
For Moderate severe atopic dermatitis:
Duplilamb- Anti IL-4/13
Contact Dermatitis treatment
For highly edematous, vesicular and exudative eruptions:
Eliminate Allergen,
Astringent soaked in 1: 10,000 solution of potassium permagnet (KMnO4),
Burrow’s solution (Aluminium Acetate 1%),
Emollients.
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