Differential Diagnosis for Small, Round, White Areas on Chest and Arms

• Single Most Likely Diagnosis
  • Tinea corporis (ringworm): This is a common fungal infection that causes small, round, white patches on the skin, often with a red ring around them. The description of "small tinnia coprus" suggests a fungal infection, and tinea corporis is a likely cause given the location and appearance of the lesions.
• Other Likely Diagnoses
  • Pityriasis alba: A mild, chronic skin condition characterized by small, round, white patches on the face, arms, and chest. It is often associated with eczema or atopic dermatitis.
  • Seborrheic keratoses: Benign skin growths that can appear as small, round, white or light brown patches on the skin, often on the chest and arms.
  • Vitiligo: A condition that causes loss of skin pigment, resulting in small, round, white patches on the skin, although it can occur anywhere on the body.
• Do Not Miss Diagnoses
  • Cutaneous lymphoma (e.g., mycosis fungoides): A rare type of skin cancer that can cause small, round, white or red patches on the skin. While unlikely, it is essential to consider this diagnosis to avoid missing a potentially life-threatening condition.
  • Sarcoidosis: A systemic disease that can cause small, round, white or red patches on the skin, as well as other symptoms such as fever, fatigue, and joint pain.
• Rare Diagnoses
  • Leprosy (Hansen's disease): A chronic bacterial infection that can cause small, round, white or light brown patches on the skin, often with loss of sensation or nerve damage.
  • Pityriasis versicolor: A fungal infection that causes small, round, white or brown patches on the skin, often on the chest and arms, although it is more common in tropical regions.