1. - pitting of the surface of the nail plate
Helen Imseeh
Nail psoriasis
In psoriasis nail involvement is common , most patients have nail changes at some stage
*severe nail involvement is more likely in the presence of arthritis
nail changes that may occur:
- pitting of the surface of the nail plate
‘thimble pitting'
--best-known nail change --
onycholysis (separation of the nail from the nail bed)
psoriasis under the nail plate, showing up as red or brown areas resembling oil spots
These findings are most often found in the fingernails.
Psoriasis in the toenails can be indistinguishable from onychomycosis.
There is no effective topical treatment for psoriasis of the nails.

2. staphylococcal infections
Bacterial infections
staphylococcal infections
Quick revision
Staphylococci are gram-positive spherical cells
nonmotile
usually arranged in grapelike irregular clusters.
-Staphylococcus species are facultative
Some are members of the normal microbiota of the skin and mucous membranes of humans
such as
Staphylococcus aureus which found in a minority who carry it in their nostrils, perineum or armpits.

3. Skin diseases caused by staph infections
Impetigo
both are highly contagious
Superficial bacterial skin infection maybe caused by Staph. aureus or Strep pyogenes
It is the most common skin infection of children
occurs particularly in tropical or subtropical regions, or during summer months in the nothern hemisphere.
Primary impetigo mainly affects exposed areas such as the face and hands, but may also affect trunk, perineum and other body sites

4. it is classified as nonbullous or bullous
large thin-walled bulla containing serous yellow fluid.
It often ruptures leaving a complete or partially denuded area with a ring or arc of remaining bulla
nonbullous type predominates and presents with cluster of erosions, or small vesicles or pustules that have an adherent or oozing
honey-yellow crust.
As a useful rule of thumb,
the bullous type is usually caused by
--Staphylococcus aureus
the crusted ulcerated type by-- β-haemolytic strains of streptococci.

5. as we said before the bullous type is usually caused by Staphylococcus aureus
that's by producing Exfoliative toxins which cleave superficial skin adhesion molecule desmoglein 1 to disrupt adhesion high in the epidermis, causing the stratum corneum to slough off.
If the toxin is localized this produces the blisters of bullous impetigo but
if generalized leads to more widespread blistering as in the staphylococcal scalded skin syndrome.

6. Course
It tends to clear even without treatment.
Complications
Streptococcal impetigo can trigger an acute glomerulonephritis.
Differential diagnosis
Herpes simplex
eczema.
Recurrent impetigo of the head and neck, for example, should prompt a search for scalp lice.
Investigation
The diagnosis is usually made on clinical grounds.
Gram stains can be done or swabs can be taken for culture,
" but treatment must not be held up until the results are available."
treatment minor cases:
-removal of crusts by compressing them
-application of a topical antibiotic such as neomycin, fusidic acid , mupirocin or bacitracin
severe cases:
Systemic antibiotics (such as flucloxacillin, erythromycin or cefalexin) or if anephritogenic strain of streptococcus is suspected (penicillin V).

7. Scalded skin syndrome
Characterized by fever and generalized erythematous rash and tenderness which are followed by the loosening of large areas of overlying epidermis .
⊕ Nikolsky sign (gentle strokes result in exfoliation)
In children the condition is usually caused by a toxin produced by staphylococcal infection elsewhere (e.g. impetigo or conjunctivitis
Seen in:
- newborns and children,
-adults with renal insufficiency .
most adults have antibodies to the toxin, and therefore are protected.
In adults with widespread exfoliation, consider toxic epidermal necrolysis, which is usually drug-induced.
The damage to the epidermis in toxic epidermal necrolysis is full thickness, and a skin biopsy will distinguish it from the scalded skin syndrome

8. Folliculitis is inflamed hair follicles.
The result is a tender red spot, often with a surface pustule. Folliculitis may be superficial or deep, and can affect any hair-bearing area of skin.
A furuncle (syn. boil) is a deeper, and more pronounced infection of the hair follicle in which purulent material extends through the dermis into the subcutaneous tissue, where a small abscess forms.
A carbuncle is a coalescence of several inflamed follicles into a single inflammatory mass with purulent drainage from multiple follicles

9. furuncle Adolescent boys are especially susceptible to them.
Presentation and course
A tender red nodule enlarges, and later may discharge pus and its central ‘core’ before healing to leave a scar.
Fever and enlarged draining nodes are rare.
Most patients have one or two boils only, and then clear.

10. The sudden appearance of many furuncles suggests a virulent staphlococcus including strains of community-aquired MRSA, or staphylococci expressing Panton–Valentine leucocidin toxin.
A few unfortunate persons suffer from a tiresome sequence of boils (chronic furunculosis), often due to susceptibilty of follicles or colonization of nares or groins with pathogenic bacteria.
Immunodeficiency is rarely the problem.
Complications
Cavernous sinus thrombosis is an unusual complication of boils on the centralface. Septicaemia may occurbut is rare.
Investigations
in chronic furunculosis
General examination: look for underlying skin disease (e.g.scabies,pediculosis,eczema).
Test the urine for sugar. Full blood count.
Culture swabs from lesions and carrier sites (nostrils,perineum) of the patient and immediate family.
Test both to identify the organism and to evaluate sensitivity to various antibiotics. Immunological evaluation only if the patient has recurrent or unusual internal infections too.

11. Treatment Acute episodes:
simple incision and drainage.
An appropriate systemic antibiotic is needed
-when many furuncles are erupting
-when fever is present,
-when the patient is immunosuppressed.
In recurrent furunculosis:
treat carrier sites such as the nose twice daily for the first 5 days of each month with an appropriate topical antiseptic or antibiotic (e.g.mupirocin cream or fusidic acid ointment) to try to eliminate staphylococcal carriage.
A 10-day course of rifampicin may also help eradicate carriage. Treat family carriers in the same way.
In stubborn chronic cases long-term treatment with
sequential topical and systemic antibiotics chosen to cover organism’s proven sensitivities will be needed.
Daily bath using an antiseptic soap.
Improve hygiene and nutritional state, if faulty.

12. Carbuncle
A group of adjacent hair follicles becomes deeply infected with Staphylococcus aureus, leading to a swollen painful suppurating area discharging pus from several points.
The pain and systemic upset are greater than those of a boil.
Diabetes must be excluded. Treatment
needs both topical and systemic antibiotics.
Incision and drainage has been shown to speed up healing,
Consider the possibility of a fungal kerion in unresponsive carbuncles.

13. Streptococcal infections
Quick revision
Staphylococci are gram-positive spherical cells
nonmotile
characteristically form pairs or chains during growth.
-some are members of the normal human microbiota

14. Erysipelas
Infection involving upper dermis and superficial lymphatics, usually from S pyogenes. Presents with well-defined demarcation between infected and normal skin
The first warning of an attack is often malaise, shivering and a fever. After a few hours the affected area of skin becomes red, and the eruption spreads with awell-defined advancing edge.
Blisters may develop on the red plaques

15. treatment
Untreated, the condition can even be fatal, but it responds rapidly to systemic penicillin, sometimes given intravenously.
The choice of oral or parenteral route is dictated by the severity of the infection.
Recurrence occurs in up to 20% of erysipelas patients.
Unlike lightning, erysipelas often strikes in the same place twice. Recurrent bouts may need long-term prophylactic penicillin

16. Cellulitis
-Acute, painful, spreading infection of deeper dermis and subcutaneous tissues.
(deeper level than erysipelas )
- Usually from S pyogenes or S aureus.
-Often starts with a break in skin from trauma or another infection
area is more raised and swollen, and the erythema less marginated than in erysipelas
Toe web intertrigo and lymphoedema are risk factors for the development of both erysipelas and cellulitis, which in turn predispose patients to persistent lymphoedema. It is important to get theseunderlying factors as well as the bacterial infection to reduce the risks of recurrence.

17. Treatment:
-elevation and rest
-systemic antibiotics, sometimes given intravenously and active against both staphylococci and streptococci.
A combination of a macrolide with a streptogramin may be more effective than penicillins.