An intense itch on the scalp can be frustrating and painful. Pruritus is the medical term for itching. According to PsoriasisNet, pain and pruritus have a few common neurophysiologic pathways, which explains why these two sensations overlap in some cases. There are a number of medical conditions that can cause scalp rashes that lead to painful and intense itching.

Seborrheic Dermatitis

Mainly affecting the scalp, seborrheic dermatitis causes red, itchy skin and can create dandruff. It's associated with a reaction to the overgrowth of yeast on the surface of the skin in people who are genetically predisposed. There are a number of over-the-counter medications to help combat it, including dandruff shampoos. It's often confused with scalp psoriasis, but seborrheic dermatitis scales are thicker and confined to the scalp alone, says MayoClinic.com.

Sunburn

A sunburn on the scalp can be extremely painful and ultimately very itchy. Try an anti-inflammatory medication or cold compress for immediate relief.

Head Lice

Head lice are tiny parasitic insects found on people's heads. According to MayoClinic.com, these can cause painful irritation, but, to help cure the problem, there are over-the-counter medicines and shampoos that contain pyrethrin (Rid, for example) or permethrin (Nix).

Scalp Psoriasis

A long-lasting and persistent skin disease that can develop almost anywhere on the body, including the scalp, psoriasis causes red patches and silvery scaling. This scaling results from the rapid growth of skin cells. It can be merely an inconvenience or debilitating. Psoriasis usually requires the attention of a medical professional but can be treated with nonprescription cortisone cream in the short term.

Folliculitis

A bacterial infection of the hair follicles, folliculitis causes itching and can lead to scarring or permanent hair loss. There are many varieties of folliculitis, all of which are best treated by a doctor.

Source:

MayoClinic.com: Psoriasis

PsoriasisNet