Clinical Features of Common Skin Conditions Sebaceous Cyst Definition: A sebaceous cyst, also known as an epidermal cyst, is a non-cancerous, closed sac located beneath the skin filled with keratin, a protein component of hair, nails, and skin. • • • • • Appearance: Smooth, round or oval-shaped lump beneath the skin, ranging in size from pea-sized to several centimeters. Texture: Firm, movable, and often painless unless infected. Location: Commonly found on the face, neck, chest, and back. Symptoms: Usually asymptomatic but may become tender, red, or inflamed if infected. Complications: Infection can lead to pain, swelling, and drainage of purulent material. Keratoacanthoma Definition: A rapidly growing, dome-shaped benign tumor that resembles squamous cell carcinoma but typically regresses spontaneously. • • • • • Appearance: Initially appears as a small, flesh-colored or pink papule that rapidly grows over weeks to form a crater-like lesion with a central keratin plug. Location: Commonly on sun-exposed areas such as the face, hands, and forearms. Growth: Rapid growth phase followed by stabilization and spontaneous regression over several months. Symptoms: Often asymptomatic but can ulcerate and bleed if traumatized or infected. Differential Diagnosis: Differentiated from squamous cell carcinoma by its clinical course and histological features. Warts (Verrucae) Definition: Warts are benign skin growths caused by human papillomavirus (HPV) infection affecting the epidermis. • • • • Appearance: Vary in appearance depending on the type of HPV: o Common Warts: Firm, rough, raised papules with a rough surface, often with black dots (thrombosed capillaries). o Plantar Warts: Flat, thickened lesions with a rough surface on the soles of feet. o Genital Warts: Soft, pink or flesh-colored growths on genital mucosa. Location: Common warts on fingers, hands, and knees; plantar warts on feet; genital warts on genital and anal areas. Transmission: Direct contact with HPV-infected skin or surfaces. Treatment: Can resolve spontaneously but may require treatment with topical treatments (salicylic acid, cryotherapy) or surgical removal for persistent warts. Skin Abscess Definition: A localized collection of pus within tissues caused by bacterial infection, typically Staphylococcus aureus. • • • • • Appearance: Red, swollen, tender area with a fluctuant mass (pus collection) beneath the skin surface. Symptoms: Pain, warmth, swelling, and sometimes fever if the abscess is large or spreading. Location: Can occur anywhere on the body, often in areas with hair follicles and sebaceous glands. Risk Factors: Poor hygiene, compromised immune system, diabetes, and skin injuries. Treatment: Incision and drainage (I&D) to release pus, followed by antibiotics if systemic symptoms are present or if the infection spreads. Summary Each of these skin conditions presents with distinct clinical features that aid in diagnosis and management. Understanding their typical appearances, locations, symptoms, and associated risk factors is crucial for accurate diagnosis and appropriate treatment planning in clinical practice. Early recognition and intervention can often prevent complications and improve patient outcomes, ensuring effective management of these common dermatological conditions.