Skin Repair, Burns, and Integumentary Disorders

Severe burns often require surgical intervention through skin grafts to restore the protective barrier. There are several types of grafts available:

• Autograft: Tissue is taken from the patient's own body.
• Allograft (Homograft): Tissue is harvested from a human donor.
• Xenograft (Heterograft): Tissue is harvested from an animal donor.
• Artificial skin: Man-made materials used to cover wounds.

Aging and the Integumentary System

As the body ages, the integumentary system undergoes significant physiological changes that reduce its efficiency. Key changes include a decrease in the number of functioning melanocytes (which provide pigment), Langerhans cells (which assist in immune response), and the production of Vitamin D3.

These cellular declines lead to several clinical observations:

• Skin becomes drier and more prone to damage.
• Repair rates slow down significantly.
• The skin loses elasticity, leading to sagging and wrinkles.
• The ability to regulate body temperature becomes impaired.

Clinical Note: Sunlight exposure can accelerate these aging effects, causing the skin to age more rapidly than it would in a protected environment.

Integumentary Disorders

Diseases of the skin can be categorized by their underlying cause, ranging from inflammation to infectious agents.

Inflammatory Disorders

These often involve inflammation of the papillary layer of the dermis. Common conditions include:

• Eczema: A chronic inflammatory condition.
• Dermatitis: Often triggered by exposure to chemicals, radiation, or mechanical stress.
• Seborrheic dermatitis: A specific type of inflammatory skin condition.
• Psoriasis: A chronic condition affecting skin cell turnover.

Infections

The skin is a frequent site for various infectious agents:

• Bacterial: Includes acne and impetigo (which can sometimes occur as a secondary infection from a burn).
• Viral: Common examples are chicken pox, warts, and cold sores.
• Fungal: Includes ringworm and athlete’s foot.

Other Conditions

Other notable disorders include decubitus ulcers (bedsores), which are caused by ischemia (lack of blood flow) and subsequent necrosis (tissue death). Additionally, changes in skin color can indicate systemic issues, such as jaundice (often related to liver issues) or vitiligo (loss of pigment).

Skin Cancer

Skin cancers are the most serious integumentary disorders and are categorized by the specific cells they originate from:

1. Basal Cell Carcinoma: This originates in the stratum basale. It often forms open ulcers and, while it requires treatment via surgery or radiation, it is usually not metastatic.
2. Squamous Cell Carcinoma: This forms a keratin nodule and is commonly found on the scalp, ears, lips, or the back of the hands. It typically requires surgical removal, but there is a good chance of recovery if detected early.
3. Malignant Melanoma: This is the most dangerous form of skin cancer, often arising from a preexisting mole. It is highly prone to metastasis (spreading to other parts of the body), and delayed treatment often leads to death.

Exam Tip: The ABCD Criteria When evaluating potential malignant melanoma, clinicians use the ABCD criteria (Asymmetry, Border, Color, Diameter) to assess the risk of malignancy.