How do you know if you have lice or dandruff my head is always itchy?

Examine your scalp. Lice lay eggs called nits on the hair near your scalp. Nits adhere to the hair while flakes from dandruff are easily brushed off. If you cannot wash or brush the particles off you may have lice. If you are not sure, see your doctor to confirm. The treatment for lice is sold over the counter at any pharmacy.
Itchy Scalp. If you have head lice you can see them. Seborrheic dermatitis is a common skin condition that mainly affects your scalp. It causes scaly patches, red skin and stubborn dandruff. Seborrheic dermatitis can also affect oily areas of the body, such as the face, upper chest and back. Try TGeonor Nizoral (ketoconazole) Shampoo.
Lice. Lice can itch a lot. Lice may be tan to brown gray & the size of a sesame seed. Nits are tiny, light to white colored deposits that adhere to hair. Head lice may be on back of head, neck, eye brows or behind ears. They cause pink to red bumps w central dot.

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Unbearably itchy upper body & scalp. No scabies, lice, dandruff, or allergies (tested). Rashes on hands/inner elbows/chest. Steroid cream not helping?

See Allergist. Given you unbearable itching symptoms and rash refractory to topical steroids I would suggest making an appointment to see an allergist for further workup/evaluation. Eczema, contact dermatitis, urticaria (hives), etc. are all skin condition that you could be suffering from. Getting workup up by a specialist might provide more answers/treatments. Read more...