This article was originally published in a sponsored newsletter.

Introduction

Atopic dermatitis (AD) is a specific form of eczema and the most prevalent chronic inflammatory skin disease.¹ This chronic disorder is associated with pruritus and usually starts in infancy. It presents with dry skin, scaling, papules, plaques, vesicles, eczematous lesions and lichenification. AD is associated with other Immunoglobulin E (IgE)-associated conditions, including allergic rhinitis, conjunctivitis, asthma and food allergies, as well as significant cutaneous and ocular morbidity. The prevalence of AD has been increasing up to threefold for the past few decades.²

Etiology

Complex genetic and environmental factors leading to epidermal and immunologic pathology characterize AD. If one parent is atopic, there is a more than 50% chance that their offspring will develop atopic symptoms. If both parents are affected, up to 80% of offspring will be affected. Loss-of-function mutations in filaggrin (Filament Aggregating Protein)—an epidermal protein that is broken down into natural moisturization factors—may drive AD.³ Filaggrin mutations are present in up to 30% of AD patients and may also predispose patients to ichthyosis vulgaris, allergic rhinitis and keratosis pilaris.⁴ Food hypersensitivity may also cause or exacerbate AD in 10% to 30% of patients. Indeed, eggs, milk, peanuts, soy and wheat cause 90% of such reactions.⁵ Recent studies indicate that adult-onset AD may be associated with obesity and smoking.⁶

Epidemiology

AD appears in 10% to 30% of children and 2% to 10% of adults in developed countries. It has a higher incidence at higher latitudes, likely corresponding to decreased actinic exposure and lower humidity. Early-onset AD from birth to two years old is the most common type. Approximately 60% of cases start by age one, while another 60% resolve by age 12. Late-onset AD usually begins with puberty, and senile-onset AD (which is rare) begins at age 60 or older.⁷

Pathophysiology

The characteristic cutaneous barrier defect may be caused by decreased ceramide levels, which are sphingolipids in the stratum corneum. Inflammation mediators include Th1 and Th2 responses, with elevated IL-1, IL-4, IL-5, IL-6, TNF Alpha, IL-12 and IFN-gamma. Microbial colonization and decreased anti-microbial peptides, such as beta-defensins and cathelicidins, predispose patients to secondary infections.¹

Diagnosis

AD is typically a clinical diagnosis, although adjunctive skin biopsy, serum allergen fluorescent enzyme immunoassay or skin prick testing can also be useful. Differential diagnoses include allergic contact dermatitis, lichen simplex, lichen planus, psoriasis, candididasis, scabies, tinea and seborrhea.

Complications include kaposi varicelliform eruption linked to primary herpetic infections; keratosis pilaris; secondary bacterial infection, usually with streptococcus or staphylococcus; impetiginization and urticaria.

Treatment

The four major treatment pillars are trigger avoidance, daily skin care, anti-inflammatory therapy and complementary modalities. Persistent and recurrent itching is costly to control and significantly affects quality of life. Probiotics, prebiotics, bleach baths, UVA and UVB phototherapy, topical calcineurin inhibitor tacrolimus, topical steroids, phosphodiesterase inhibitor topical ointment (such as Crisaborole)⁸ and systemic cyclosporine, azathioprine, mycophenolate mofetil, methotrexate, pulse prednisone or dupilumab injections can improve symptoms.⁹ However, dupilumab ironically may cause ocular surface disease.¹⁰

Prevention

Cotton and silk¹¹ garments are preferred and mild laundry detergents are recommended,⁷ along with cooler home temperatures to avoid sweat and itch. Patients should also use sunscreen with moisturizers and indoor humidification to prevent drying. Food and contact allergens, tobacco, dander, fumes, fragrances, pollen, soaps, detergents, synthetic fabrics and wool should be avoided.

Regular ocular examinations are indicated to screen for dry eye, cataract, retinal detachment, blepharitis, glaucoma, keratoconjunctivitis and keratoconus,¹² especially because corneal shield ulcers can lead to permanent visual impairment due to ectatic axial scarring.¹³

Prognosis

Most AD patients improve with age, but approximately 30% develop allergic rhinitis, asthma or both. Mild to moderate symptoms often persist for a decade or more, and around 80% of patients need topical medications for symptom control.¹⁴ In most cases of childhood-onset AD, the disorder persists for multiple decades. Because AD has relapses and remissions, patients should expect to use medications whenever relapses occur.

References

1. Paller A, Jaworski JC, Simpson EL, et al. Major comorbidities of atopic dermatitis: beyond allergic disorders. Am J Clin Dermatol. 2018 Dec;19(6):821-838. doi:10.1007/s40257-018-0383-4
2. Kolb L, Ferrer-Bruker SJ. Atopic dermatitis. StatPearls. Updated August 8, 2023. Accessed October 9, 2024. https://www.ncbi.nlm.nih.gov/books/NBK448071/
3. Smieszek SP, Welsh S, Xiao C, et al. Correlation of age-of-onset of atopic dermatitis with Filaggrin loss-of-function variant status. Sci Rep. 2020 Feb;10:2721. doi:10.1038/s41598-020-59627-7
4. Oliveira ADT, Sodré CS, Ferreira DC, et al. Oral aspects identified in atopic dermatitis patients: a literature review. Open Dent J. 2018 May;12:424-434. doi:10.2174/1874210601812010424
5. Mehta Y, Fulmali DG. Relationship between atopic dermatitis and food allergy in children. Cureus. 2022 Dec;14(12):e33160. doi:10.7759/cureus.33160
6. Ali Z, Ulrik CS, Agner T, Thomsen SF. Association between atopic dermatitis and the metabolic syndrome: a systematic review. Dermatology. 2018;234(3-4):79-85. doi:10.1159/000491593
7. Kowalska-Olędzka E, Czarnecka M, Baran A. Epidemiology of atopic dermatitis in Europe. J Drug Assess. 2019;8(1):126-128. doi:10.1080/21556660.2019.1619570
8. Napolitano M, Marasca C, Fabbrocini G, Patruno C. Adult atopic dermatitis: new and emerging therapies. Expert Rev Clin Pharmacol. 2018 Sep;11(9):867-878. doi:10.1080/17512433.2018.1507734
9. Ariëns LFM, Bakker DS, van der Schaft J, Garritsen FM, Thijs JL, de Bruin-Weller MS. Dupilumab in atopic dermatitis: rationale, latest evidence and place in therapy. Ther Adv Chronic Dis. 2018 Sep;9(9):159-170. doi:10.1177/2040622318773686
10. Foley P, Kerdraon YA, Hogden JP, et al. Dupilumab-associated ocular surface disease: an interdisciplinary decision framework for prescribers in the Australian setting. Australas J Dermatol. 2022 Nov;63(4):421-436. doi: 10.1111/ajd.13924
11. Thomas KS, Bradshaw LE, Sach TH, et al. Randomised controlled trial of silk therapeutic garments for the management of atopic eczema in children: the CLOTHES trial. Health Technol Assess. 2017 Apr;21(16):1-260. doi: 10.3310/hta21160
12. Lee SH, Lee SH, Lee SH, Park YL. Cataract, glaucoma, and dry eye disease in adults with atopic dermatitis: a nationwide cross-sectional study from the Republic of Korea. Ann Dermatol. 2019 Feb;31(1):37-43. doi:10.5021/ad.2019.31.1.37
13. Stock RA, Lazzari SLT, Martins IP, Bonamigo EL. Surgical debridement of corneal shield ulcers in pediatric patients: two case reports and a review of the literature. J Med Case Rep. 2020 Jun;14(1):70. doi:10.1186/s13256-020-02407-8
14. Rastogi S, Patel KR, Singam V, Silverberg JI. Allergic contact dermatitis to personal care products and topical medications in adults with atopic dermatitis. J Am Acad Dermatol. 2018;79(6):1028-1033.e6. doi:10.1016/j.jaad.2018.07.017

John D. Sheppard, MD is a board-certified ophthalmologist and fellowship-trained corneal eye surgeon in Norfolk, Virginia.