1. Prurigo [L. “the itch”] Papules induced by scratching
The term “Besnier's prurigo” is applied to the chronic papular or lichenified form of atopic eczema

2. Nodular Prurigo
(Prurigo Nodularis)

3. Etiology The cause is unknown
Emotional stress seems to be a contributory factor in some cases
In 20% the condition starts after an insect bite
There is increase in number of neutrophils, mast cells, Merkel cells and IL-31

4. Clinically Patients are mostly middle-aged to elderly
They complain of a long-standing history of severe, unremitting pruritus and they can point out specific sites where they began feeling itchy
The patient's medical history may reveal hepatic or renal dysfunction, local trauma to the skin, infection, anxiety or other psychiatric condition

5. The early lesion is red, and
may show a variable
urticarial component
All lesions are pigmented
Crust and scale may cover
recently excoriated lesions,
and there is an irregular
ring of hyperpigmentation
immediately around the
nodules

6. The lesions are usually grouped, and numerous, but vary in number
They usually develop initially on
the distal parts of the limbs & are
worse on the extensor surfaces
There are crises of pruritus of
intense severity
New nodules develop from time to
time, and existing nodules may remain pruritic indefinitely, although some may regress spontaneously to leave scars. The disease runs a very protracted course

7. Treatment
Local applications are of little value, but direct injection of the nodules with a steroid such as triamcinolone is often helpful
Thalidomide is probably the most effective treatment, if it is not contraindicated by the risk of pregnancy
Menthol, capsaicin cream, and topical anesthetics are some other topical agents used to reduce pruritus

8. Cyclosporin, azathioprine and topical capsaicin have been used with success in some cases
UV-B or PUVA may be beneficial for severe pruritus
A thorough assessment of the patient's emotional state is desirable, and tranquillizers may provide relief in some cases

9. Surgical Care
Cryotherapy with liquid nitrogen helps reduce pruritus and flatten lesions
Pulsed dye laser therapy may help reduce the vascularity of individual lesions.

10. Erythroderma

11. It is a scaling erythematous dermatitis involving 90% or more of the cutaneous surface

12. Etiology The most common causes of ED are (ID-SCALP(:
Idiopathic(red man syndrome) - 30%
Drug allergy(Allopurinol, aspirin, anticonvulsants, barbiturates, captopril, cefoxitin, chloroquine, chlorpromazine, cimetidine, lithium, griseofulvin, nitrofurantoin, omeprazole) - 28%
Different types of eczema - 15%
Lymphoma and leukemia - 14%
Psoriasis - 8%

13. Less common causes Dermatophytosis Lichen planus Lupus erythematosus
Pityriasis rubra pilaris
Pemphigus foliaceus and pemphigoid

14. An increased skin blood perfusion occurs resulting in heat loss and hypothermia and possible high-output cardiac failure
Fluid loss by transpiration is increased. The situation is similar to that observed in patients following burns (negative nitrogen balance characterized by edema, hypoalbuminemia, loss of muscle mass)

15. A marked loss of exfoliated scales occurs that may reach 20-30 g/d
A marked loss of exfoliated scales occurs that may reach g/d. This contributes to the hypoalbuminemia commonly observed in ED. Hypoalbuminemia results, in part, from decreased synthesis or increased metabolism of albumin
Edema is a frequent finding, probably resulting from fluid shift into the extracellular spaces

16. Clinically
Patients may have a history of the primary disease (e.g. psoriasis, atopic dermatitis)
or drug use
Pruritus is a prominent and frequent symptom and commonly results in excoriations. Malaise, fever, and chills may occur

17. Patients often present with
generalized erythema
Scaling appears 2-6 days
after the onset of erythema,
usually starting from flexures
When ED persists for weeks,
hair may shed; nails may become ridged and thickened and also may shed
Periorbital skin may be inflamed and edematous, resulting in ectropion

19. Idiopathic ED is characterized by marked palmoplantar keratoderma, dermatopathic lymphadenopathy, and a raised level of serum IgE and is more likely to persist than other types
Residual signs of the original disease may be found e.g.:
- Islands of sparing in PRP
- Few typical psoriatic plaques in psoriasis
- Papules or oral lesions of lichen planus
- Superficial blisters of pemphigus foliaceus

20. Investigations
If the cause of ED is in doubt, survey patients for occult tumors
Primary disease may be evident by skin biopsy

21. Treatment
Discontinue all unnecessary medications. Carefully monitor and control fluid intake, since patients can dehydrate or go into cardiac failure; monitor body temperature, since patients may become hypothermic
Apply tap water–wet dressings (made from heavy mesh gauze); change every 2-3 hours. Apply intermediate-strength topical steroids (e.g. betamethasone) beneath wet dressings

22. Suggest a tepid bath (may be comforting) once or more daily between dressing changes. Reduce frequency of dressings and gradually introduce emollients between dressing applications as ED improves
Use systemic antibiotics if signs of secondary infection are observed

23. Antihistamines help reduce pruritus and provide needed sedation
Systemic steroids may be helpful in some cases but should be avoided in suspected cases of psoriasis and staphylococcal scalded skin syndrome
Ensure adequate nutrition with emphasis on protein intake