Anal Itching- Pruritis ani.

Anal itching is itching around anus. The itch, situated in the anus or on the skin just around the anus, Itching is intense with a strong urge to scratch, which could be embarrassing and uncomfortable.

Causes

1. Intestinal parasites, 
2. Anal perspiration, frequent liquid stools,  
3. Diarrhoea, residual stool deposits, or the escape of small amounts of stool as a result of incontinence or flatulence. Another cause is yeast infection or candidiasis. Some diseases increase the possibility of yeast infections, such as diabetes mellitus or HIV infection. Treatment with antibiotics can bring about a disturbance of the natural balance of intestinal flora, and lead to perianal thrush, a yeast infection, affecting the anus. Psoriasis also can be present in the anal area and cause irritation. Abnormal passageways (fistulas) from the small intestine or colon to the skin surrounding the anus can form as a result of disease (such as Crohn's disease), acting as channels which may allow leakage of irritating fluids to the anal area. Other problems that can contribute to anal itching include pinworms, hemorrhoids, tears of the anal skin near the mucocutaneous junction (fissures), and skin tags (abnormal local growth of anal skin). Anal itching is conjectured to be possibly caused by irritating chemicals in foods consumed, but no clinical evidence based on scientific enquiry has been asserted to demonstrate this.

Some authorities describe “psychogenic pruritus” or "functional itch disorder", where psychological factors may contribute to awareness of itching.

Treatment

Identification of the cause and treating it appropriately and to rule out diabetes mellitus.

PRURITUS VULVAE

Vulvar Pruritis is an exceedingly common gynecologic problem.
Causes are-
Dermatologic conditions like allergic or contact irritant dermatitis, Lichen simplex, psoriasis, Lichen planus, Paget's disease, erythema multiforme, Bowen's disease, etc
Intravaginal foreign bodies
Herpes Simplex
Cervicitis
Pediculosis Pubis
Molluscum contagiosum
Gonorrhea
Candida
Vaginal sinuses and fistulae
Diabetes mellitus
Pregnancy

Gynecological examination is essential  is essential in any patient with persistent pruritus vulvae.
Excessive discharge can cause maceration and irritation, and it is virtually impossible to produce any relief of the itching until this is brought under control.

Gianotti-Crosti Syndrome

Viruses like EBV, CMV, Hepatitis B virus, coxsackievirus, parainfluenza virus, Respiratory syncytial virus, rota virus, adenovirus, poliao virus, parvovirus, HIV, hepatitis A and C virus along with some bacteria like Mycoplasma Pnumonia, group A streptococcus cause an immune response to transient viremia (immune complex deposition). Usually occurs in children aged 6 months to 12 year old.
Initially there is mild, nonspecific, upper respiratory infection.
Discrete, non-itchy, red, papules appearing over buttocks, face, arms and legs. Trunk is not involved.
Duration is almost 2-8 weeks.
The condition is self limiting.