What are the common skin diseases in adults?

Common Skin Diseases in Adults

Skin cancer is the most common type of cancer affecting adults, with basal cell carcinoma (75% of cases), squamous cell carcinoma (20%), and melanoma (1%) being the primary malignancies, while non-malignant conditions like tinea pedis, onychomycosis, rosacea, actinic keratosis, and asteatotic eczema affect the majority of the adult population. 1, 2

Malignant Skin Diseases

Skin Cancers: Epidemiology and Clinical Significance

• Basal cell carcinoma accounts for 75% of all skin cancers, rarely metastasizes, and is highly curable but represents the most common malignancy in adults 1
• Squamous cell carcinoma comprises 20% of skin cancers, has metastatic potential to lymph nodes and internal organs, and accounts for approximately 20% of all skin cancer deaths despite being less common than basal cell carcinoma 1
• Melanoma represents only 1% of skin cancers but causes 75% of skin cancer deaths, with approximately 53,600-70,000 new cases annually and 7,400-8,800 deaths 1

Melanoma-Specific Characteristics

• Melanoma incidence has more than doubled since 1973, increasing from 5.7 per 100,000 to 27.6 per 100,000 in white Americans by 2008 1
• Melanoma is 20-30 times more common in white persons than in Black persons, though persons with darker skin are often diagnosed at later, more difficult-to-treat stages 1
• The disease most commonly appears on the trunk in men and lower legs in women, though it can occur on the head, neck, or elsewhere 1
• Melanoma is nearly always curable in early stages but becomes deadly when detected late 1

Non-Malignant Skin Diseases

Most Prevalent Conditions in Adults

Nearly 80% of adults aged 70 and older have at least one skin disease requiring treatment or follow-up, with more than one-third having three or more simultaneous skin conditions. 2

• Tinea pedis (athlete's foot) affects 48.6% of older adults, making it the single most common skin disease 2
• Onychomycosis (fungal nail infection) occurs in 29.9% of older adults 2
• Rosacea affects 25.5-25.6% of the general adult population 3, 2
• Actinic keratosis (precancerous lesions) occurs in 22.3-26.6% of adults, representing a significant precursor to squamous cell carcinoma 3, 2
• Asteatotic eczema (dry skin dermatitis) affects 20.8% of older adults and is particularly common in hospitalized geriatric patients 4, 2

Additional Common Conditions

• Eczema affects 11.7% of the general adult population 3
• Seborrhoeic dermatitis is frequently encountered in geriatric medicine wards 4
• Incontinence-associated dermatitis is common among hospitalized older adults 4
• Chronic venous insufficiency and cellulitis are prevalent in geriatric populations 4

Risk Factors and Demographics

Age and Gender Patterns

• Skin diseases increase significantly with age, with the highest burden in adults aged 70 and older 3, 2
• Men have a higher prevalence of skin diseases (72.3%) compared to women (58.0%) 3
• Men aged 65 and older account for 22% of newly diagnosed melanoma cases annually, while women in the same age group account for 14% 1
• The lifetime risk of dying from melanoma is 0.36% in white men and 0.21% in white women 1

Awareness Gap

Clinical examinations reveal that nearly two-thirds (64.5%) of adults with skin abnormalities are unaware of their conditions, indicating a substantial unmet diagnostic need. 3

Clinical Implications for Practice

Screening Considerations

• The USPSTF concludes that current evidence is insufficient to assess the balance of benefits and harms of visual skin examination by clinicians to screen for skin cancer in asymptomatic adolescents and adults (I statement) 1
• Despite insufficient evidence for population-based screening, whole-body clinical skin examinations are important in older adults because they reveal important diagnoses that patients are unaware of 2
• Hospitalization of older adults presents an opportunity to diagnose and manage unmet dermatologic needs unrelated to their admission 4

Prevention Strategies

• For individuals aged 10-24 years with fair skin, the USPSTF recommends counseling about minimizing UV radiation exposure to reduce skin cancer risk (B recommendation) 1
• For adults older than 24 years, evidence is insufficient to assess the balance of benefits and harms of counseling to prevent skin cancer (I statement) 1
• Sun-protective behaviors include using broad-spectrum sunscreen with SPF ≥15, wearing protective clothing and hats, avoiding outdoors from 10 a.m. to 3 p.m., and avoiding indoor tanning 1

Common Pitfalls to Avoid

• Underestimating disease burden: Skin diseases are the fourth most common cause of human illness globally, yet many affected individuals do not seek medical care, leading to underestimation of true prevalence 3
• Focusing only on younger populations: Older adults, especially elderly men, bear a disproportionate burden of morbidity and mortality from both melanoma and non-melanoma skin cancers 1
• Neglecting multiple concurrent conditions: More than one-third of older adults have three or more simultaneous skin diseases, requiring comprehensive assessment rather than single-disease focus 2
• Missing precancerous lesions: Actinic keratosis affects over one-quarter of adults and represents a significant precursor to squamous cell carcinoma that requires identification and management 3, 2