Sycosis Vulgaris and Furunculosis

Study Notes

A boil is an acute, round, tender, and circumscribed follicular staphylococcal abscess that generally ends in central suppuration.
A carbuncle is two or more confluent furuncles with separate heads.
Predisposing factors for boils include:
- Impaired skin integrity due to irritation, friction, hyperhidrosis, dermatitis, or shaving.
- Presence of a contagion or autoinoculation from a carrier focus, usually in the nose or groin.
- Systemic disorders such as malnutrition, blood diseases, diabetes, or AIDS.

Lesions begin in hair follicles and often continue for a prolonged period by autoinoculation.
Some lesions disappear before rupture, but most undergo central necrosis and rupture through the skin, discharging purulent, necrotic debris.
Commonly involved sites are the face, neck, arm, wrist, fingers, buttocks, and anogenital region.
Treatment includes topical and systemic antibiotics, as well as incision and drainage of some cases.

Cellulitis is an infection of the subcutaneous tissue, while erysipelas is more superficial, involving the dermis and upper subcutaneous tissue.
Both are caused mainly by Streptococcus pyogenes.
Clinical features of erysipelas include:
- Well-demarcated and raised edges of the lesion.
- Blistering and hemorrhage are more common.
- Lymphangitis and lymphadenopathy are frequent.
The face and legs are the most frequent sites affected.
Unusual complications include gangrene, metastatic abscesses, and grave sepsis.
Treatment typically involves systemic penicillin and cephalosporins.

Erythrasma is a mild, chronic, localized superficial infection of the skin.
It is more common in adults.
Etiology is Corynebacterium minutissimum.
Predisposing factors include a warm and humid climate, and diabetes mellitus.
Clinical picture includes:
- Patches that are sharply marinated, dry, brown, and slightly scaling in intertriginous areas.
- Coral red fluorescence on Wood's light examination.
Treatment includes topical azole antifungals and oral erythromycin in extensive cases.

Common staphylococcal infections include folliculitis, furunculosis, carbuncle, and impetigo.
Common streptococcal infections include erysipelas, cellulitis, impetigo, and ecthyma.

Definition: Impetigo is a contagious superficial pyogenic infection of the skin caused by staphylococci and streptococci.
It is a mixed staphylococcal and streptococcal infection that affects neonates.