**6. References**

Bek-Thomsen, M., Lomholt, H.B., & Kilian, M. (2008). Acne is not associated with yetuncultured bacteria. *Journal of Clinical Microbiology* Vol. 46, No. 10, pp. 3355-3360

Fig. 10. Multiple verruca vulgaris on the eyelid of an adult patient with AD.

As microorganisms have close and complex relationships with human skin, doctors and scientists should be aware of the presence of good and harmful species in the skin. Human skin has mechanisms to allow microbes to reside on the skin, and good microbes may help

On the other hand, certain microbes may trigger AD under certain conditions and others are consistent pathogens. When considering microorganisms as exacerbating factors, research should be performed in order to clarify their roles. Such research may lead to advances in

In treatment of various infectious conditions in AD patients, careful and well-considered

I thank Prof. Haroun N. Shah, London for the insightful comments on this manuscript. This work is partly supported by Grant-in-Aid 22791073 from the Ministry of Education,

Bek-Thomsen, M., Lomholt, H.B., & Kilian, M. (2008). Acne is not associated with yet-

uncultured bacteria. *Journal of Clinical Microbiology* Vol. 46, No. 10, pp. 3355-3360

**4. Conclusion** 

the treatment and prevention of AD.

**5. Acknowledgment** 

**6. References** 

strategy by dermatologists is necessary.

Culture, Sports, Science and Technology (MEXT) of Japan.

humans.


**8** 

*Japan* 

**Atopic Dermatitis and Skin** 

Takashi Sugita1, Enshi Zhang3, Takafumi Tanaka1, Mami Tajima3,

*1Department of Microbiology, Meiji Pharmaceutical University, Kiyose, Tokyo 2Department of Immunobiology, Meiji Pharmaceutical University, Kiyose, Tokyo 3Department of Dermatology, Tokyo Medical University, Shinjuku, Tokyo* 

A wide variety of bacteria and fungi are found on the human skin. Although some skin microorganisms produce antibacterial peptides that inhibit invasion by pathogens or promote the integrity of cutaneous defenses by eliciting host immune responses, the normal

Atopic dermatitis (AD) is a chronic disease that causes pruritus and involves cycles of remission and deterioration. AD is the result of dry hypersensitive skin. When the skin is dry, the protective barrier function of the cutaneous surface horny layer is compromised, and the skin readily develops dermatitis in response to various external stimuli, including skin microorganisms. Serum from almost all AD patients contains IgE antibodies against some skin microorganisms. For example, staphylococcal superantigen-specific IgE is present in the serum of AD patients, but not in the serum of healthy individuals. Normally, the weakly acidic condition of healthy skin prevents colonization by *Staphylococcus aureus*. However, in patients with AD, the skin pH is shifted toward neutrality, allowing *S*. *aureus* to

In the cutaneous fungal microbiome, lipophilic yeasts of the genus *Malassezia* are the predominant species on human skin. As *Malassezia* species require lipids for growth, they preferentially colonize sebum-rich areas such as the head, face, and neck, as opposed to the limbs or trunk. Specific IgE antibody against *Malassezia* species is found in the serum of AD patients. Antifungal therapy improves the symptoms of AD by decreasing the level of *Malassezia* colonization, suggesting that these microorganisms also exacerbate AD. *Malassezia* species, unlike *S*. *aureus*, colonize both AD patients and healthy subjects. Currently, the genus *Malassezia* consists of 14 species. Of these, *M*. *globosa* and *M*. *restricta* have been detected in almost all AD patients, suggesting that these two *Malassezia* species play a significant role in AD. The level of specific IgE antibody against both species is

This chapter discusses cutaneous fungi as an exacerbating factor in AD, focusing on:

**1. Introduction** 

grow and exacerbate AD.

microbiome can also cause several skin diseases.

greater than that against other *Malassezia* species.



Ryoji Tsuboi3, Yoshio Ishibashi2, Akemi Nishikawa2

**Fungal Microorganisms** 

filaggrin gene by novel shotgun method in Japanese atopic dermatitis. *Journal of Dermatological Science* Vol. 51, No. 2, pp. 113-120

Sugita, T., Tajima, M., Amaya, M., Tsuboi, R., & Nishikawa, A. (2004). Genotype analysis of *Malassezia restricta* as the major cutaneous flora in patients with atopic dermatitis and healthy subjects. *Microbiology and Immunology* Vol. 48, No. 10, pp.755-759
