Scalp psoriasis, seborrheic dermatitis and dandruff are the most common scalp conditions that can be treated using OTC pharmacy products.

Dandruff is a scalp condition caused by a build-up of dead skin cells in the scalp which collects together to form white clumps that can be seen on the hair and often fall onto the shoulders. As well as looking unpleasant, dandruff may also be itchy.
Treatments options for dandruff include, Oilatum Scalp Treatment Shampoo, Oilatum Scalp Intensive Treatment Shampoo, Selsun Dandruff Treatment, T-gel Shampoo, etc.

Seborrhoeic dermatitis is a type of skin inflammation that can cause severe dandruff and affect other areas of the body. In more serious cases, patches of red, scaly, greasy skin may develop. Yellow-brown crusts can form on top of these patches, which may be itchy and slightly raised. In severe cases, this rash can affect most of the face, scalp, neck, armpits, chest and groin.
An antifungal shampoo can be used to treat seborrheic dermatitis, however if it does not control the problem then your GP may prescribe an oral antifungal or antibiotic treatment.

Scalp psoriasis causes red patches of skin covered in thick, silvery-white scales. This condition may be itchy for some and mild for others, however severe cases can lead to temporary hair loss.
Tar shampoo, gels and ointments are commonly used to treat scalp psoriasis, but they all need to be used regularly. They may be combined with other ingredients, such as salicylic acid to help remove scale, or coconut oil to moisturise the skin.

Signposting:

www.embarrassingproblems.com
www.nhs.uk/conditions/dandruff