Itch inhibition due to pain
Studies done in the last decade have shown that itch can be inhibited by many other forms of painful stimuli, such as noxious heat, physical rubbing/scratching, noxious chemicals, and electric shock. Causes
Infections
Body louse, found in substandard living conditions
Cutaneous larva migrans, a skin disease
Head lice, if limited to the neck and scalp
Herpes, a viral disease
Insect bites, such as those from mosquitos or chiggers
Pubic lice, if limited to the genital area
Scabies, especially when several other persons in close contact also itch
Shaving, which may irritate the skin
Swimmers itch, a short-term immune reaction
Varicella – i.e. chickenpox, prevalent among young children and highly contagious
Tungiasis, ectoparasite of skin

Environmental and allergic
Allergic reaction to contact with specific chemicals, such as urushiol, derived from poison ivy or poison oak, or Balsam of Peru, found in many foods and fragrances. Certain allergens may be diagnosed in a patch test. Foreign objects on the skin are the most common cause of non-pathological itching. Photodermatitis – sunlight reacts with chemicals in the skin, leading to the formation of irritant metabolites. Urticaria (also called hives) usually causes itching. Skin disorders
Dandruff; an unusually large amount of flaking is associated with this sensation. Punctate palmoplantar keratoderma, a group of disorders characterized by abnormal thickening of the palms and soles. Skin conditions (such as psoriasis, eczema, seborrhoeic dermatitis, sunburn, athletes foot, and hidradenitis suppurativa). Most are of an inflammatory nature. Scab healing, scar growth, and the development or emergence of moles, pimples, and ingrown hairs from below the epidermis.
However, in children a throat culture is recommended to confirm the result. Asymptomatic individuals should not be routinely tested with a throat culture or RADT because a certain percentage of the population persistently "carries" the streptococcal bacteria in their throat without any harmful results. Differential diagnosis
As the symptoms of streptococcal pharyngitis overlap with other conditions, it can be difficult to make the diagnosis clinically. Coughing, nasal discharge, diarrhea, and red, irritated eyes in addition to fever and sore throat are more indicative of a viral sore throat than of strep throat. The presence of marked lymph node enlargement along with sore throat, fever, and tonsillar enlargement may also occur in infectious mononucleosis. Other conditions that may present similarly include epiglottitis, Kawasaki disease, acute retroviral syndrome, Lemierres syndrome, Ludwigs angina, peritonsillar abscess, and retropharyngeal abscess. Prevention
Tonsillectomy may be a reasonable preventive measure in those with frequent throat infections (more than three a year). However, the benefits are small and episodes typically lessen in time regardless of measures taken. Recurrent episodes of pharyngitis which test positive for GAS may also represent a person who is a chronic carrier of GAS who is getting recurrent viral infections. Treating people who have been exposed but who are without symptoms is not recommended. Treating people who are carriers of GAS is not recommended as the risk of spread and complications is low. Treatment
Untreated streptococcal pharyngitis usually resolves within a few days. Treatment with antibiotics shortens the duration of the acute illness by about 16 hours.