Which layer of the skin is involved in cellulitis?

Central Institute of Psychiatry - 9 July 2022

Medical & Surgical Nursing

Easy

Appeared in: Central Institute of Psychiatry - 9 July 2022

Explanation

Cellulitis is a bacterial infection that extends into the deeper layers of the skin.
The primary layers affected are the dermis (the thick layer beneath the epidermis) and the hypodermis (the subcutaneous fat layer).
This deeper involvement explains the characteristic signs of cellulitis: a diffuse, non-demarcated area of redness, warmth, swelling, and tenderness.
Common causative organisms include Streptococcus pyogenes and Staphylococcus aureus, which enter through breaks in the skin.

Option B: This option describes a more superficial infection. While the dermis is involved, the inclusion of the epidermis as a primary site is more characteristic of other conditions.
Option C: This is incomplete. While cellulitis always involves the dermis, a key feature is its extension into the deeper subcutaneous tissue (hypodermis).
Option D: This option is a description of a condition, not just the layers involved. It is more descriptive of impetigo, which is a superficial infection of the epidermis often caused by Staphylococcus.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Anatomical layers of skin involved in cellulitis as background academic context rather than a clinical decision trigger.
A key nursing intervention is to mark the outer border of the erythema with a permanent marker. This allows for easy and objective monitoring of the infection's spread or response to treatment.
Elevating the affected limb is crucial to reduce swelling (edema), decrease pain, and improve lymphatic drainage, which aids in recovery.
Nurses must monitor for signs of systemic infection or sepsis, such as fever, tachycardia, hypotension, and confusion. Rapid progression of redness or development of purple bullae are red flags for necrotizing fasciitis, a surgical emergency.

How to Approach the Question

First, identify the core of the question, which is asking for the specific anatomical location of cellulitis within the skin layers.
Recall the three main layers of the skin: Epidermis (outermost), Dermis (middle), and Hypodermis/Subcutaneous (deepest).
Mentally classify common skin infections by their depth. Think of Impetigo as most superficial (epidermis), Erysipelas as intermediate (upper dermis), and Cellulitis as deep (dermis and hypodermis).
Evaluate each option against this classification. 'Hypodermis and Dermis' accurately describes the deep nature of cellulitis.
Eliminate other options. 'Epidermis and Dermis' is too superficial. 'Dermis' alone is incomplete. The option mentioning staphylococcus is describing etiology, not just anatomical layers.

Concept Tested & Keywords

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E6 Medicine Harrison 22e Part 1 pp. 1090-1092, 1093-1095