Dermatological Practice: Characteristics of Skin Diseases in Children and the Elderly

Dr. Noriko Sato

Accessible Rail Medical Services Tetsuikai, Navitas Clinic Tachikawa,

Department of Dermatology, Tokyo, Japan

Before joining Navitas Clinic Tachikawa in 2015, I was a full-time physician at the Public Akiruno Medical Center. This center is located in Akiruno City in the western part of Tokyo, and due to its close ties with neighboring long-term care hospitals and senior health facilities, many of our patients come via referrals. This resulted in a particularly aged patient demographic. Thus, my areas of expertise before joining Navitas were skin ulcers, foot care, and the treatment of bedsores.

However, once I began working at Navitas Clinic Tachikawa that located in a station building in one of the large hub stations in Tokyo, the patient demographic shifted dramatically. The clinic bustled with younger patients daily, and while initially overwhelming, this transition marked the beginning of a new chapter in my dermatological practice and learning. Now, my areas of specialty have become pediatric skin diseases in general, particularly atopic dermatitis. As I still attend to the elderly at the Akiruno Medical Center once a week, I diagnose a wide range of skin conditions across all ages, making every day both hectic and rewarding.

When I analyzed the average age of patients visiting for dermatological consultations in a particular month, I found that at Navitas Clinic it was 27 years old, while at the Akiruno Medical Center it was 78 years old. Even within the same metropolitan area in Tokyo, the patient age demographic can differ so vastly based on location and community. Naturally, the types of skin conditions I encounter vary substantially. In this piece, I aim to elucidate the characteristics of skin diseases in children and the elderly, taking into account the skin changes that come with age.

Characteristic Pediatric Skin Diseases

Some representative skin diseases in children include contagious impetigo ("tobihi" in Japanese), molluscum contagiosum ("water warts"), and common warts. There are also various eczematous skin diseases such as infantile eczema, diaper dermatitis, seborrheic dermatitis in infants, and pediatric atopic dermatitis. Many of these conditions are related to the relative weakness of a child's skin immunity.

When a baby emerges from the mother's womb, their skin – often described as the largest human organ – is suddenly exposed to the air. The skin of children, with its immature immune system, has to continuously adapt to various external factors like pathogens, humidity, and temperature variations, gradually increasing its immunity. During this adaptive process, they are more prone to the aforementioned skin diseases.

An "immature immune system" implies that the skin's barrier function is not yet fully developed. Although skin thickness varies depending on the area, a newborn's skin is said to be about half as thick as that of an adult. Moreover, in children, the stratum corneum, which is the outermost layer of the skin, is particularly thin, and with the unstable secretion of sebum, their skin is more susceptible to external irritants and pathogenic invasion. Thus, the skin's barrier function is underdeveloped, making it prone to drying out and, as a result, more susceptible to infections and eczema. Therefore, it is crucial to maintain adequate moisture to compensate for this immature barrier function.

By ensuring proper moisturization from the neonatal stage, the risks of skin infections and eczema can be substantially reduced. Understanding the immaturity of a child's skin barrier function allows clinicians to confidently respond to concerns from guardians, such as, "Why does my child need to moisturize so rigorously?" with comprehensive explanations that are easy to grasp.

Characteristic Skin Diseases in the Elderly

When listing characteristic skin diseases in the elderly, we can mention conditions such as seborrheic eczema due to reduced skin oils, age spots ("shimi" in Japanese), seborrheic dermatitis, solar keratosis, seborrheic keratosis (senile warts), ulcerative dermatitis, pressure sores, malignant skin tumors, fungal skin infections, and blistering diseases. Many of these conditions are influenced by skin aging, an inevitable process that affects everyone as they grow older.

Skin aging can be categorized into two types: intrinsic aging due to age, and photoaging caused by sun exposure. In intrinsic aging, the thickness of the three layers of the skin (epidermis, dermis, and subcutaneous tissue) decreases, leading to reduced skin elasticity. There's also a decline in sebaceous and sweat gland activity, making the skin more prone to dryness. Furthermore, the number of blood vessels in the skin decreases, and their walls weaken. This aging process makes the skin thinner, more fragile, and harder to heal after minor damages.

On the other hand, photoaging results from chronic exposure to UV rays, especially affecting areas like the face, neck, and back of the hands. It exacerbates the effects of intrinsic aging. Specific symptoms include rough and less elastic skin that becomes darker, presenting with age spots, wrinkles, and senile warts. Pre-cancerous lesions such as solar keratosis and malignant skin tumors can also develop. Studies using mice have shown that sunscreen is effective in preventing and slowing the progression of photoaging. There are also reports in humans suggesting that using sunscreen can prevent solar keratosis and malignant skin tumors. Thus, applying sunscreen and protective clothing are recommended to prevent photoaging.

I often receive skin-related consultations from elderly patients. In response to skin dryness resulting from intrinsic aging, I always emphasize the importance of "applying moisturizers thoroughly over the entire body." Similarly, for various skin symptoms arising from photoaging, I strongly advocate for the diligent application of sunscreen, even if someone has never taken UV protection measures before, regardless of their gender.

The Importance of Moisturizers

From what has been discussed thus far, a common characteristic of the skin of both children and the elderly is its tendency to "dry easily". This highlights the importance of moisturizers. Therefore, let's briefly discuss moisturizers.

Typical moisturizers prescribed in dermatology include heparin analogs, urea preparations, and petrolatum (Vaseline). Heparin analogs have the ability to absorb moisture and provide water to the stratum corneum, ensuring sustained moisturizing effects. Urea preparations, similar to heparin analogs, absorb moisture to supply water to the stratum corneum, and also possess keratolytic (horn-softening) properties. Petrolatum acts as an oily film that covers the skin, preventing the evaporation of its moisture. The most frequently used heparin analogs come in various forms (ointments, creams, lotions) with different water-to-oil ratios. Depending on the individual's skin condition and the state of its barrier function, we adjust the type of formulation prescribed.

The barrier function of the skin can be quantitatively assessed by measuring both the moisture content of the stratum corneum and the transepidermal water loss (the amount of water that evaporates through the stratum corneum, not through sweat glands). However, the specialized equipment required for such measurements is typically found only in major facilities.

Hence, in practice, I often physically touch the patient's skin to roughly estimate the moisture content and water loss, guiding my choice of moisturizer. Directly touching the patient's skin during a consultation (unless there's a risk of infection) can sometimes provide reassurance to the patient, and it often serves as the first step in building a trusting relationship with them.

The Three "Observations" in Dermatology

What inspired me to pursue a career in dermatology was a lecture I attended during my first dermatology class at Saga Medical University (now Saga University), my alma mater. The lecture was delivered by Professor Hiroshi Narusawa, who was then the Professor of Dermatology. I'd like to share an excerpt from his talk. In Japanese, the kanji characters '見る', '診る', and '看る' all can be read as "miru (observations)", but they each have their distinct meanings: to look, to diagnose, and to attend/take care of, respectively.

"In dermatology, three types of 'observation' are essential. The first is '見る' (look). Looking with one's eyes is the most crucial step in a dermatological examination. Next is '診る' (diagnose). Diagnose based on the information you see with your eyes and the knowledge you possess. Finally, there's '看る' (attend or take care). Palpation is essential. Touch the patient's skin with your hands, observe with your eyes, and communicate with the patient. That is '看る' (attend). Indeed, this kanji character includes symbols for both 'hand (手)' and 'eye (目)'. Those who aspire to specialize in dermatology should practice these three 'observations'."

Whenever I face challenges in dermatological practice, I always remember Professor Narusawa's words and press on.

*List of related papers from Navitas Clinic: https://www.megri.or.jp/navitasclinic

About the Author

Dr. Noriko Sato

Accessible Rail Medical Services Tetsuikai, Navitas Clinic Tachikawa, Department of Dermatology, Tokyo, Japan

Graduated from Saga Medical School in 2004. Following initial training at Kyorin University Hospital, in 2006, She joined the Department of Dermatology at the same institution. At Kyorin University Hospital, her focus was on diagnosing drug eruptions and working in the allergy outpatient clinic. After serving at the Public Akiruno Medical Center, she assumed a full-time position at Navitas Clinic Tachikawa in 2015, while also taking on a part-time role at the Akiruno Medical Center. Currently, she is dedicated to the latest treatments for atopic dermatitis, catering to skin concerns across all age groups, from newborns to the elderly. She is a certified dermatologist of the Japanese Dermatological Association.