Skin infections

Skin infections: When microbes overcome the defense

The skin is our primary protective barrier that guards against the entry of microorganisms. However, when this barrier is damaged (by cuts, scratches, abrasions) or when immunity is weakened, bacteria, fungi, or viruses can penetrate the skin, causing an infection. Skin infections can be superficial or deep, localized or widespread.

Bacterial infections (Pyoderma)

These are purulent diseases most often caused by the bacteria Staphylococcus aureus (staph) and Streptococcus pyogenes (strep), which are part of the normal skin microflora but become pathogenic when its integrity is compromised.

• Impetigo: A highly contagious superficial infection that is common in children. It is characterized by blisters that quickly turn into honey‑yellow crusts.
• Folliculitis, furuncle, carbuncle: Purulent inflammation of hair follicles and surrounding tissue, varying in depth and extent.
• Cellulitis (phlegmon): A deep infection of the skin and subcutaneous tissue that presents with diffuse redness, swelling, pain, and elevated temperature. Requires systemic antibiotic treatment.

Fungal infections (Mycoses)

Caused by dermatophyte fungi or yeast‑like fungi (Candida). They proliferate in warm, moist environments.

• Dermatophytoses ("ringworm"): Affect the skin, nails, and hair. On the skin they appear as characteristic circular red patches.
• Candidiasis: Most often affects skin folds.

Viral infections

Viruses can also cause specific skin lesions such as herpes, chickenpox, herpes zoster, molluscum contagiosum, warts. Read about pediatric skin infections in the relevant section.