In older adults, atopic dermatitis (AD) often departs from classic childhood or adult morphology [1, 2]. Instead of well-demarcated flexural eczema, the disease may present with:

• Prominent xerosis (dry skin) and excoriations, often linear and crusted from chronic scratching [1, 3, 4]
• Distribution over extensor and truncal surfaces rather than flexural creases [2, 5]
• Minimal erythema but intense pruritus (itch) as the dominant feature [1, 3]
• Association with personal or family history of atopy (asthma, allergic rhinitis, eczema) [6, 7]
• Recurrent infections due to barrier compromise and impaired immune response [4]

This “itch-dominant atopic dermatitis” phenotype is easily mistaken for other chronic pruritic dermatoses but should be suspected in an elderly patient with chronic, relapsing itch and an atopic background.

Key Differentiators:

• Prurigo Nodularis (B): discrete nodules or papules rather than linear excoriations .
• Allergic contact dermatitis (C): usually localized to sites of allergen exposure; patch testing aids confirmation [8].
• Scabies (D): burrows and involvement of finger webs, umbilicus, or genitalia; nocturnal itch and contact history typical [9].
• Cutaneous T-cell lymphoma (Mycosis Fungoides) (E): persistent patches or plaques in photoprotected areas; may have poikiloderma or lymphadenopathy [10].

References:

1. Weidinger S, Novak N. Atopic dermatitis. Lancet. 2021;398(10302):110-122.
2. Boguniewicz M, Leung DYM. Atopic Dermatitis: Pathogenesis and Treatment. In: Kang S, Amagai M, Bruckner AL, et al., editors. Fitzpatrick’s Dermatology. 9th ed. McGraw Hill; 2019. p. 306-328.
3. Zheng Y, Yu B, Ma L, et al. Clinical Characteristics of Atopic Dermatitis in the Elderly. Dermatology. 2021;237(3):477-484.
4. Silverberg JI, Gelfand JM, Margolis DJ, et al. Health care utilization, costs, and disease severity in atopic dermatitis in the adult US population. Ann Allergy Asthma Immunol. 2015;114(5):378-385.
5. Leung DYM, Guttman-Yassky E. Deciphering the complexities of atopic dermatitis: shifting paradigms in treatment approach. Nat Rev Immunol. 2023;23(4):216-231.
6. Spergel JM. Epidemiology of atopic dermatitis and atopic march in children. Immunol Allergy Clin North Am. 2010;30(3):269-280.
7. Thyssen JP, Halling-Overgaard AS, Egeberg A. Atopic dermatitis-a chronic disease in adults. J Eur Acad Dermatol Venereol. 2020;34 Suppl 4:3-11.
8. Usatine RP, Riojas V. Diagnosis and management of contact dermatitis. Am Fam Physician. 2010;82(3):249-255.
9. Strong M, Johnstone PW. Interventions for treating scabies. Cochrane Database Syst Rev. 2007;(3):CD000381.
10. Olsen EA, Kim YH, Nasti TH, et al. Revisions to the Staging and Classification of Mycosis Fungoides and Sezary Syndrome: A Proposal of the International Society for Cutaneous Lymphomas (ISCL) and the cutaneous Lymphoma Task Force of the European Organization of Research and Treatment of Cancer (EORTC). Blood. 2011;118(11):3504-3512.