How can I differentiate between atopic eczema and other skin conditions in a patient presenting with pruritic dermatitis?

To differentiate atopic eczema from other skin conditions in a patient presenting with pruritic dermatitis, consider the following clinical features and history:

• Atopic eczema typically presents as an itchy skin condition with visible flexural dermatitis involving skin creases such as the bends of the elbows or behind the knees, or in children under 18 months, dermatitis on the cheeks and/or extensor areas. A history of previous flexural dermatitis or dry skin in the last 12 months supports the diagnosis.
• Additional diagnostic criteria include a personal or family history of atopic diseases such as asthma or allergic rhinitis, and onset of symptoms under the age of 2 years (though this criterion is not used in children under 4 years).
• In some ethnic groups (Asian, Black Caribbean, Black African), atopic eczema may affect extensor surfaces rather than flexures and may present with discoid or follicular patterns, which can help distinguish it from other dermatoses.
• Other skin conditions may lack the chronic relapsing nature, typical distribution, or associated atopic history seen in atopic eczema.
• Consider the impact of the condition on quality of life and psychosocial wellbeing, as atopic eczema often causes significant itch, sleep disturbance, and psychosocial effects.
• When diagnosis is uncertain or the presentation is atypical, referral for specialist dermatological advice is recommended.

Summary: Diagnosis is clinical, based on characteristic distribution (flexural or extensor in young children), chronicity, pruritus, dry skin, personal/family atopy, and exclusion of other causes. Use of validated tools and holistic assessment can aid differentiation and severity assessment.

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