What is a White circle rash doing on my arm and leg?

There could be several possible reasons for a white circular rash on your arm or leg. While it's important not to self-diagnose, here are a few potential causes:

1. Ringworm (Tinea): Ringworm is a common fungal infection of the skin. It appears as round, itchy, red, or white patches with raised edges. It can spread to different body parts, including arms and legs.

2. Pityriasis Alba: This is a harmless skin condition that often affects children and young adults. It presents as dry, scaly, round or oval white patches, usually on the arms, legs, or face.

3. Eczema or Dermatitis: Different types of eczema, such as atopic dermatitis or contact dermatitis, can cause dry, inflamed skin, including white patches. These rashes can appear anywhere on the body.

4. Vitiligo: Vitiligo is a chronic skin disorder where patches of skin lose their pigment, leading to white or light-colored spots. It can affect various areas of the body, including arms and legs.

5. Tinea Versicolor: Tinea versicolor is a fungal infection that causes white, brown, or pink patches on the skin, often on the arms, legs, back, or chest. It tends to be more noticeable during warm weather.

6. Sun Exposure: Sunburn or sun damage can cause temporary white patches on the skin. These usually resolve over time.

7. Allergic Reactions: Some people may develop white patches or rashes as an allergic reaction to certain allergens.

8. Insect Bites or Stings: Insect bites or stings can sometimes cause white or itchy patches on the skin.

If the white circles are persistent, spreading, accompanied by other symptoms, or cause significant discomfort, it's essential to consult a healthcare provider for an accurate diagnosis and appropriate treatment. They can determine the exact cause and recommend the best course of action. Self-medication without a proper diagnosis is not recommended.