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Terminology:

  • Eczema is a Greek word ( Ec means out , and Zeo means boil).
  • The whole word implies ‘boil out’. The hindusthani name for eczema is chambal.

Definition:

  • Eczema is reaction pattern of non- contagious inflammatory response of skin characterized clinically in acute stage by erythema , vesiculation , oozing and crusting and in chronic stages by scaling and lichenification.
  • It is a specific type of allergic cutaneous manifestation of antigen – antibody reaction.

Classification:

  • Eczema is grouped into 2 types :
    • 1) exogenous eczema
    • 2) endogenous eczema

Exogenous eczema:

  • Contact dermatitis
  • Infective dermatitis
  • Photodermatitis

Endogenous eczema:

  • Atopic dermatitis
  • Seborrheic dermatitis
  • Nummular eczema
  • Stasis eczema
  • Asteatotic eczema
  • Pityriasis alba
  • Lichen simplex chronicus
  • And also Prurigo nodularis

Eczema

Morpho – clinical classification:

Epidermis:

  • Acute eczema : In the epidermis, it is characterized by spongiosis, i.e. intercellular edema.
  • Intraepidermal vesicles form by the disruption of intercellular attachments.
  • Subacute : parakeratotic stratum corneum forms and acanthotic process starts.
  • The rete ridges broaden and also get elongated.
  • Chronic : rete ridges broaden and elongated further.
  • Hyperkeratosis replaces parakeratosis.

 

Dermis:

      • Vasodilatation in the papillary dermis and also lympho – histiocytic infiltrate accompanies it.
      • Polymorphs and eosinophils are seen in acute eczema and in chronic stage infiltration is dense and mixed.

    Etiology:

        • Dermatitis and also eczema are a common problem all over the world.
        • Their incidence is 2-3 per cent of all medical problems in practice.
        • Despite this confusion, the two terms ‘Dermatitis’ and ‘Eczema are in synonymous use by the dermatologists.
        • Moreover, in the practice of dermatology, the first step is to establish the clinical diagnosis of dermatitis and eczema then decide the clinical -morphological pattern.

      Basically two factors causes eczema are ,

          • Allergic or sensitive skin
          • And also Exposure to an irritant

        Other factors responsible ;

            • Irritants – physical, chemical or electrical
            • Sensitizers – plants, cosmetics, clothing, medicaments and occupational hazards
            • Infections – streptococci, staphylococci, fungus etc.
            • Mental and emotional conflicts, strains and stresses
            • Internal septic focus shedding toxins or causing bacteraemia
            • Diet and state of digestion.
            • Diathesis – allergic, xerodermic, hyperhidrotic or seborrhoeic
            • Drugs – given for the disease or otherwise
            • State of local or general nutrition
            • And also Climate – temperature and humidity

          General predisposing causes:

              • Firstly, Age
              • Secondly, Familial predisposing
              • Thirdly, Allergy
              • Debility
              • Climate
              • Finally, Psychological factors

            Exogenous eczema:

            Contact dermatitis:

                • It is an inflammatory process in skin.
                • The cause is by an exogenous agent or agents that directly or indirectly injure the skin.
                • Injury by a direct toxic action on the skin – refers to irritant contact dermatitis (ICD).
                • Agents that causes allergic contact dermatitis (ACD) induce an antigen- specific immune response.
                • The most common cause of contact dermatitis are ; plants, clothing and footwear, cosmetics, occupational chemicals, medicaments.
                • Removal of the offending agent is the first and foremost step.
                • And so the eruption will resolve.
                • Moreover, Administration of high – potency fluorinated topical glucocorticoid is the choice of treatment.

              Infective dermatitis:

                  • This results from sensitization to certain organisms like streptococci, staphylococci, dermatophytes and yeast organisms.
                  • It’s more common in tropical countries.
                  • About three-fourths of hospital eczema cases fit into this category.
                  • Clinically it is characterized by its slow development, so no vesicles is evident but a crust is formed instead.
                  • The patches formed are clearly defined, and there is no erythematous halo, they take the form of circles which by union become polycyclic.
                  • The lesion spread not only by direct contiguity but also to the other body folds, parts and hair follicles.
                  • Infective eczema can be divided further into three sub-types according to their distribution: post traumatic infective eczema, follicular infective eczema, flexural infective eczema.
                  • These eczema responds to mild antiseptic astringents.

                Photodermatitis:

                    • Photodermatitis resembles an exaggerated sunburn reaction commonly due to phototoxic drugs like psoralens.
                    • It is confined to the exposed parts of the body viz., Face, neck, hands, and external surfaces of the forearms and dorsa of feet and the adjoining parts of leg.
                    • The integument is sensitive to sunlight and ultraviolet rays. Eruption develops, or becomes aggravated on exposure to light.
                    • The common causes of photodermatitis are:
                    • 1)drugs like sulphonamides, chlorpromazine, promethazine, declamycin, different hypotensive and anti-diabetic drugs, quindexin in animal feeding stuff etc.
                    • 2) foods like figs, buckwheat
                    • 3) external application of bithionol, tetrachlorsalicylanilide etc.
                    • 4) plants and their products like parsnips, meadow grass, mustards, limeoil, celery, etc.
                    • Predisposing factors are: vitamin B complex deficiency, porphyrinuria, seborrhoeic diathesis and liver disorders.

                    Treatment:

                    • Firstly, Reassuring the patient , relatives about the disease being curable, non infectious and non scarring.
                    • Secondly, Elimination of predisposing, exciting and complicating causes.
                    • Thirdly, to desensitize or hyposensitize the patient.
                    • Correction of the environment is more important.
                    • Moderate atmospheric temperature and humidity improves the condition.
                    • Rest to the affected part is mandatory.
                    • Bed rest is necessary in generalized eczema.
                    • Internal or systemic therapy: No specific medicine or injections can cure eczemas.
                    • The few drugs available for symptomatic relief only.
                    • Example: ACTH and corticosteroids, antihistamines, calcium gluconate and strontium bromide, sedatives and hypnotics ( chloral hydrate and barbiturates)
                    • Local treatment: sensitizing and strong medicaments should not be used locally because they produce therapeutic panic.
                    • It should be free from smell and should not produce stinging sensation.
                    • Astringents like lotion silver nitrate ½ to 1 % in aqueous solution, lotion calamine and lotion aluminium subacetate 1-5 % can be recommended to weeping eczemas.
                    • In infective eczema, the affected part is painted with gentian violet, and when this dries its covered witha medicated paste.
                    • Antibacterial cream like vioform, cetavlax, neomycin, bacitracin can be employed.
                    • In chronic eczema steroids and other allied local preparations, crude tar, tar paste and superficial x ray therapy can be tried.

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