All links accessed October 28 2019.

1. M Yaldiz. ‘Dermatological diseases in the geriatric age group: Retrospective analysis of 7092 patients’. Geriatrics Gerontology International. July 2019. 19;7:582-585 https://onlinelibrary.wiley.com/doi/abs/10.1111/ggi.13665

2. A Gonzalez-Cantero et al. ‘Do Dermatologic Diagnosis Change in Hot vs Cold Periods of The Year? A Sub-Analysis of the DIADERM National Sample (Spain 2016)’. ACTAS Dermo-Sifiliográcas. Published online July 19 2019. https://www.actasdermo.org/en-do-dermatologic-diagnosis-change-in-avance-S1578219019301763

3. VL Pascoe & AB Kimball. ‘Seasonal variation of acne and psoriasis: A 3-year study using the Physician Global Assessment severity scale’. JAAD. September 2015. 73;3:523-525. https://www.jaad.org/article/S0190-9622(15)01740-5/fulltext

4. J Klode et al. ‘Relationship between the seasonal onset of chronic venous leg ulcers and climatic factors’. JEADV. December 2011. 25;12:1415-1419. https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1468-3083.2011.03988.x

5. A Zink et al. ‘Medical needs and major complaints related to pruritus in Germany: a 4‐year retrospective analysis using Google AdWords Keyword Planner’. JEADV. January 2019. 33;1:151-156. https://onlinelibrary.wiley.com/doi/full/10.1111/jdv.15200

6. Q Wu et al. ‘Seasonality and global public interest in psoriasis: an infodemiology study’. Postgraduate Medical Journal. Published online September 11 2019. https://pmj.bmj.com/content/early/2019/09/10/postgradmedj-2019-136766

7. JD Miller. ‘Seasonal trends in incidence of herpes labialis (“cold sores”) outbreaks: An infodemiological analysis using internet search engine query data’. Value in Health. May 2013. 16;3:A83.  https://www.valueinhealthjournal.com/article/S1098-3015(13)00452-X/fulltext

8. J Silverberg et al. ‘Climatic Factors Are Associated with Childhood Eczema Prevalence in the United States’. JID. July 2013. 133;7:1752-1759. https://www.jidonline.org/article/S0022-202X(15)36320-X/fulltext

9. AB Fleischer. ‘Atopic dermatitis: the relationship to temperature and seasonality in the United States’. International Journal of Dermatology. April 2019. 58;4:465-471. https://onlinelibrary.wiley.com/doi/abs/10.1111/ijd.14289

10. World Health Organization. ‘WHO guidelines on hand hygiene in health care. First Global Patient Safety Challenge – Clean Care is Safer Care’. 2009. https://www.who.int/gpsc/5may/tools/9789241597906/en/

11. PA Kolarsick et al. ‘Anatomy and Physiology of the Skin’. Journal of the Dermatology Nurses' Association. July-August 2011. 3;4:203-213. https://journals.lww.com/jdnaonline/fulltext/2011/07000/Anatomy_and_Physiology_of_the_Skin.3.aspx

12. A Fujiwara et al. ‘Age-related and seasonal changes in covalently bound ceramide content in forearm stratum corneum of Japanese subjects: determination of molecular species of ceramides’. Arch Dermatol Res. Published online September 4 2018. 310: 729. https://link.springer.com/article/10.1007/s00403-018-1859-z

13. J Hill et al. ‘A new covalently bound ceramide from human stratum corneum –ω‐hydroxyacylphytosphingosine’. Int J Cosmetic Science. June 2006. 28;3:225-230. https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1467-2494.2006.00324.x

14. E Berardesca & J Fluhr. ‘Corneocyte Size and Cell Renewal: Effects of Aging and Sex Hormones’. In: Farage M.A., Miller K.W., Maibach H.I. (eds) Textbook of Aging Skin. Springer, Berlin, Heidelberg. 2010. pp371-375. https://link.springer.com/referenceworkentry/10.1007%2F978-3-540-89656-2_36

15. L Cau et al. ‘Lowering relative humidity level increases epidermal protein deimination and drives human filaggrin breakdown’. J Dermatological Science. May 2017. 86;2:106-113. https://www.jdsjournal.com/article/S0923-1811(16)30943-4/fulltext

16. KA Engebretsen. PhD Thesis. ‘Effect of environmental and climatic exposures on adult skin’. National Allergy Research Centre, Department of Dermatology and Allergy, Herlev and Gentofte Hospital, University of Copenhagen. November 2017. https://www.videncenterforallergi.dk/forskning/publikationer/phd-afhandlinger/

17. KA Engebretsen et al. ‘Changes in filaggrin degradation products and corneocyte surface texture by season’. BJD. May 2018. 178;5:1143-1150. https://onlinelibrary.wiley.com/doi/abs/10.1111/bjd.16150

18. Y Yoshida‐Amano et al. ‘Dry skin conditions are related to the recovery rate of skin temperature after cold stress rather than to blood flow’. International Journal of Dermatology. February 2017. 56;2:176-183. https://onlinelibrary.wiley.com/doi/full/10.1111/ijd.13436

19. KA Engebretsen et al. ‘The effect of environmental humidity and temperature on skin barrier function and dermatitis’. JEADV. February 2016. 30;2:223-249. https://onlinelibrary.wiley.com/doi/abs/10.1111/jdv.13301

20. R Fölster-Holst et al. ‘Birch pollen influence the severity of atopic eczema – prospective clinical cohort pilot study and ex vivo penetration study’. Clinical, Cosmetic and Investigational Dermatology. October 29 2015. 2015:8;539-548. https://www.dovepress.com/birch-pollen-influence-the-severity-of-atopic-eczema-ndash-prospective-peer-reviewed-fulltext-article-CCID

21. Allergy UK. Four Seasons Booklet. https://www.allergyuk.org/get-help/resources/322-four-seasons-booklet

22. T Biedermann et al. ‘Birch pollen allergy in Europe’. Allergy. July 2019. 74;7:1237-1248. https://onlinelibrary.wiley.com/doi/full/10.1111/all.13758

23. A Wassmann-Otto et al. ‘Birch pollen‐related foods can cause late eczematous reactions in patients with atopic dermatitis’. Allergy. October 2018. 73;10:2046-2054. https://onlinelibrary.wiley.com/doi/10.1111/all.13454

24. R Reekers et al. ‘Birch pollen–related foods trigger atopic dermatitis in patients with specific cutaneous T-cell responses to birch pollen antigens’. J Allergy and Clinical Immunology. August 199. 104;2:466-472. https://www.jacionline.org/article/S0091-6749(99)70395-7/fulltext

25. M Heid. ‘Here’s Why You Get More Acne in the Winter — And How to Fix It’. Time. November 14 2018. https://time.com/5454229/acne-skin-breakouts-winter/

26. A Filoni et al. ‘Association between psoriasis and vitamin D - Duration of disease correlates with decreased vitamin D serum levels. An observational case-control study’. Medicine. June 2018. 97;25:e11185. https://journals.lww.com/md-journal/fulltext/2018/06220/Association_between_psoriasis_and_vitamin_D_.68.aspx

27. NHS. Conditions. Sore or dry lips. Page last reviewed November 16 2018. https://www.nhs.uk/conditions/sore-or-dry-lips/https://www.nhs.uk/conditions/sore-or-dry-lips/

28. NHS. Conditions. Chilblains. Page last reviewed November 7 2018. https://www.nhs.uk/conditions/chilblains/

29. Primary Care Dermatology Society (PCDS). Perniosis (syn. chilblains). http://www.pcds.org.uk/clinical-guidance/perniosis

30. NICE CKS. Eczema – atopic. Last revised January 2018. https://cks.nice.org.uk/eczema-atopic

31. Primary Care Dermatology Society. Eczema: asteatotic eczema (syn. xerotic eczema, eczema craquele). http://www.pcds.org.uk/clinical-guidance/eczema-asteatotic-eczema-syn.-xerotic-eczema-eczema-craquele

32. NICE. CKS. Psoriasis. Last revised March 2018. https://cks.nice.org.uk/psoriasis

33. The Psoriasis and Psoriatic Arthritis Alliance (PAPAA). Treatments for psoriasis. https://www.papaa.org/learn-about-psoriasis-and-psoriatic-arthritis/just-diagnosed/what-is-psoriasis/treatments-for-psoriasis/

34. British Association of Dermatologists. Patient Information Leaflets. ‘Psoriasis – topical treatments’. August 2017. http://www.bad.org.uk/healthcare-professionals/psoriasis

35. BNF. Treatment summary – Psoriasis. https://bnf.nice.org.uk/treatment-summary/psoriasis.html