Understanding atopic dermatitis: pathophysiology and etiology. Conclusion

Genetic polymorphisms in serine protease inhibitor Kazal-type 5 and risk of atopic dermatitis: A meta-analysis

BACKGROUND

This study aimed to investigate the role of serine protease inhibitor Kazal-type 5 (SPINK5) polymorphisms (Asn368Ser, Asp386Asn and Glu420Lys) and the risk of atopic dermatitis (AD).

METHODS

Studies associated with SPINK5 mutations and AD risk were searched from three databases, including PubMed, Embase, and Cochrane library, with a retrieval deadline of April 22, 2019. An odds ratio (OR) with a 95% confidence interval (95% CI) was chosen as the effect size. Egger's linear regression test was enrolled to assess the level of publication bias.

RESULTS

Overall, 6 studies met the inclusion criteria for meta-analysis. Significantly statistical differences were calculated between patients with AD and healthy individuals on Asn368Ser polymorphism in the allele model (G vs A: OR = 1.2643, 95% CI = 1.0666-1.4987, P = .0069), co-dominant model (GG vs AA: OR = 1.6609, 95% CI = 1.1736-2.3505, P = .0042; GA vs AA: OR = 1.5448, 95% CI = 1.1263-2.1189, P = .0070), and dominant model (GG+GA vs AA: OR = 1.5700, 95% CI = 1.1656-2.1146, P = .0030). However, no statistically significant difference was found in the recessive model for Asn368Ser and other genetic models for Asp386Asn and Glu420Lys (all P > .05). No significant publication bias was found.

CONCLUSION

The SPINK5 Asn368Ser polymorphism may be a risk factor for AD.

Lack of Association between Exposure to Topical Calcineurin Inhibitors and Skin Cancer in Adults

BACKGROUND

Two topical calcineurin inhibitors (TCI) are available for the treatment of atopic dermatitis and there has been concern that their use could be associated with an increased risk of nonmelanoma skin cancer (NMSC).

OBJECTIVE

To determine if TCI exposure is associated with an increased risk of NMSC in adults.

METHODS

A case-control study using a questionnaire mailed to 5,000 adults with dermatitis.

RESULTS

We received responses from 70.7% of those surveyed by mail. Overall, 25.7% reported exposure to TCI. TCI exposure was 14.4% for the cases and 30.7% for the controls. Our primary analysis was a comparison between those with NMSC and those without. The unadjusted odds ratio was 0.38 (0.31-0.47) and the adjusted (age, gender, previous NMSC, history of atopic dermatitis) was 0.54 (0.41-0.69). The odds ratio of association for NMSC decreased as the number of tubes used and the potency of the agent increased.

CONCLUSION

This early study shows that TCI use is not associated with an increased risk of NMSC in adults.

The lack of a relationship between atopic dermatitis and nonmelanoma skin cancers

BACKGROUND

Very little has been published on whether a relationship exists between atopic dermatitis (AD) and skin cancer.

OBJECTIVE

The goal of this study was to investigate whether individuals with AD are more likely than other patients with dermatologic conditions to develop nonmelanoma skin cancer.

METHODS

This was a case-control, mailed-survey study.

RESULTS

Of those contacted, 69.8% (3207 of 4591) filled out the survey. Of the control patients, 18.4% (254) had a history of AD as defined by the United Kingdom Working Party diagnosis criteria and composed 13.7% (210) of the cases. The unadjusted odds ratio of AD to nonmelanoma skin cancer was 0.70 (95% confidence interval 0.57-0.85). After fully adjusting for age, sex, ethnicity, and topical steroid use the odds ratio was 0.78 (0.61, 0.98). Using different definitions of AD had little effect on this result.

CONCLUSIONS

It does not appear that patients with a history of AD are more likely to develop nonmelanoma skin cancers than other patients with dermatologic conditions.

Atopic dermatitis and fungi

Atopic dermatitis (AD) is a chronic, itching, inflammatory skin disease which is associated with asthma and/or hay fever and a familial occurrence of these conditions. Genetic factors are important in the development of AD, but the exact hereditary pathway is still unknown. Dry skin and the weakened barrier function in patients with AD is very important for the patient's reactions to irritants and other external trigger factors including microorganisms. The standard treatments are topical corticosteroids, topical immunomodulating agents, and emollients. If AD cannot be controlled by this type of treatment, systemic immunomodulating agents may be used. UVB, UVA, or psoralen-UVA may also be used for widespread severe lesions. However, some patients do not respond to these standard treatment, and then it is important to consider the role of microorganisms, house dust mites or food. The role of the Malassezia yeasts in AD, especially AD located to the head and neck region, is now documented in several papers. There are also several papers indicating the role of Candida as an aggravating factor in AD. Patients with AD also develop chronic dermatophyte infections more easily, and patients with AD and chronic dermatophyte infections may show improvement in their AD when treated with antifungal drugs.