A3-year-old child presents with eczematous dermatitis over the extensor surfaces. His mother has the history of bronchial asthma. What should be the most probable diagnosis?: (A) Atopic dermatitis, (B) Air borne contact dermatitis, (C) Seborrboeic dermatitis, (D) Infantile eczematous dermatitis
Answer is A. Ans. a. Atopic dermatitis Most probable diagnosis in a 3-year old child, who presents with eczematous dermatitis over the extensor surfaces with family history of bronchial asthma is atopic dermatitis.Atopic Dermatitis (AD)* AD is a cutaneous expression of the atopic state, characterized by a family history of asthma, hay fever or dermatitis in ~ 70% of patients.Etiopathogenesis:* Genetic predisposition: When both parents are affected, over 80% and when only one parent is affected ~50% of their children manifest the disease* Increased IgE synthesis; increased serum lgE; increased specific IgE to food, aeroaliergens. bacteria and bacterial products.* Increased expression of CD23 (low affinity IgE receptor) on monocyte and B- cells* Impaired delayed type hypersensitivity reactions.Clinical Presentation:* The clinical presentation varies with the age, half of the patients present within the first year of life, and 80% presents by 6 years of age.* The infantile pattern is characterized by weeping inflammatory patches and crusted plaques that occur on face, neck and extensor surfaces (Infantile eczema)* The childhood and adolescent pattern is marked by dermatitis of flexural skin particularly in antecubital and popliteal fossa.* Clinical course lasting longer than 6 weeksQ.* AD may resolve spontaneously, but over half of affected children will have dermatitis in adult life, i.e. course is marked by exacerbation and remissions.Pruritus and Scratching Made Worse by* Environmental alterations* Denny Morgan fold (Extra-fold of skin beneath lower eyelid).* Change in temperature, sundry (In rainy season) and rough (woolen) clothing and leading to excoriation, lichen if ication, dryness.* Increased tendency for vasoconstriction like perioral pallor and White dermatographismy.Atopic Dermatitis Associated with* Alopecia areatac* Susceptibility to skin infections0,* Antenna sign (Follicular openings are filled with horny plugs)* Head light sign (Inflammation of skin on and around lips)* Hertoghe's sign (Thinning of lateral half of eyebrows) Clinical Phase of Atopic DermatitisInfantile phaseChildhood phaseAdult phase* Rarely starts before 4-6 weeks of age and usually begins between 2-3 months of age* First begin on face0 and may quickly spread to other areas. Although, often then napkin area is relatively spared, as a result of the area being kept moist.* From one and half to two years onwards* Most characteristically involve elbow and knee flexures, wrist and ankle.* Sides of neck show a reticulate pigmentation known as atopic dirty neck.* Lichenification. especially of flexures and hands (similar to that in later childhood)* Involvement of vermilion of lip (like dermatitis)Atopic Dermatitis (AD)Clinical phase of Atopic Dermatitisinfantile phaseChildhood phaseAdult phase* Excoriation and lichenification appear at about 6 months of age, when the ability to scratch develops* Initially the disorder involves flexural distribution But when the child starts to crawl, the exposed extensor aspect of knees, are most involved.* Uncommon extensor distribution and inability to lichenify (even after prolonged rubbing) are very' difficult to treat and take longer time to remit.* Nipple involvement in young / adolescent women* Photosensitivity with ultraviolet and infrared radiation. Hanifin and Rajka Diagnostic Criteria for Atopic Dermatitis(Three major and three minor criteria should be present)Major criteria Minor criteria* Pruritus * Involvement of face and convexities in infants {<2 years) and distribution over flexures (popliteal and antecubitai fossa) in older children.,* Tendency to chronicity * Personal or family history of atopy such as asthma, allergic rhinitis or atopic dermatitis* Facial pallordeg/suborbital shadowing* Infra orbital fold (Dennie's line)* Recurrent skin infections (pyoderma, warts molluscum contagiosum)* Ichthyosis vulgaris with accentuation over palmar crease\* Tendency to non specific dermatosis of hand* Immediate skin test* Delayed blanching to cholinergics* Raised serum total IgE* Anterior subcapsular cataract * Keratoconus