The term ‘prurigo‘
designates an intensely pruritic skin lesions that have no apparent
cause. The disease is usually considered as one of the most
prurigenic skin diseases and therefore, the lesion is accompanied by
skin thickening and pigmentation.
Prurigo is characterized by the prurigo papule
that is dome-shaped and topped with a small vesicle, which usually
appears as an excoriated lesion due to severe scratching. The
crusted papules are usually seen rather than the primary papule with
its topped vesicle.
Types of Prurigo
common types of prurigo are:
1. Prurigo simplex
2. Prurigenous dermatoses
This type of prurigo appears usually in
middle-aged individuals and in both sexes .The common sites involved
are extensor surface of the extremities, trunk, face and scalp.
Fig. 290. Prurigo simplex
Fig. 291. Prurigo simplex
The clinical picture is variable, where the
prurigo papules are present as flat-topped surmounted by vesicles,
excoriated papules or in the form of lichenified pigmented skin
lesion simulating neurodermatitis or dermatitis herpetiformis.
Different clinical varieties of prurigo
Chronic prurigo of adults is a poorly defined
entity that mimics the widespread papular urticaria of insect bites.
The cause is unknown although emotional stress seems to be a
contributory factor in some cases. Insect bites especially after
repeated exposure in susceptible persons may play an important role.
The disorder is more common in adults, with an
onset in the spring and summer months. The characteristic lesions
are found on the trunk and neck, and present as itchy red papules
which occasionally coalesce to a reticular pattern, and reticular
Prurigo of this type occasionally occurs with
malignant disease, especially Hodgkin‘s
lymphoma and in polycythaemia.
Prurigo is considered as one of the
skin diseases, which causes severe and sometimes intolerable
itching, especially in emotionally unstable individuals.
Fig. 292. Nodular prurigo
Fig. 293. Nodular prurigo
The eruption consists of small, irritable
papules, usually most numerous on the extensor aspects of the limbs,
the upper trunk and the buttocks with very variable distribution.
Nodular prurigo may appear on the scalp as a
separate lesion or as a part of the disease affecting other parts of
Nodular prurigo of the scalp is not easily
differentiated from neurodermatitis. The course may be continuous
for months or years or there may be partial or complete remissions.
The individual lesion is a hard globular nodule,
1-3 cm in diameter, with a raised warty surface. The early lesion is
red and may show a variable urticarial component, but all the
lesions tend to be pigmented.
Crusting and scaling may cover recently
excoriated lesions. There is an irregular ring of hyperpigmentation
immediately around the nodules. The lesions are usually grouped.
New nodules develop from time to time, but
existing nodules may remain pruritic indefinitely although some may
regress spontaneously to leave scars. The disease runs a very long
The large, more or less symmetrical nodules and
the intense pruritus usually establish the diagnosis.
These are different diseases associated with
pruritus and papular lesions where some is accompanied by wheals,
eczematization and lichenifecation.
Different clinical types of prurigo
prurigo: This is chronic lichenified
flexural lesions and is considered as a type of atopic dermatitis.
Fig.293b. Besnier's prurigo
summer prurigo: this is an actinic
type precipitated by excessive exposure to sunlight.
Prurigo Chronica Multiformis: presents with
prurigo nodules, lichenification, eczematization, enlarged lymph
nodes and esinophilia.
prurigo - Hebra‘s
prurigo is now rarely diagnosed and its status is questionable. Most
cases occurred in atopic subjects and the role of poor nutritional
and hygienic conditions were considered as predisposing factors. The
possibility that some cases represent papular urticaria modified in
an atopic subject must be considered.
The treatment is that of atopic dermatitis.
Prurigo mitis : This type begins early in
childhood and is characterized by uniform type of small rounded,
flesh colored or erythematous, severely pruritic, flat-topped
papule, surmounted by a vesicle. Severe itching lead to excoriation,
eczematization and on healing of lesions, they may leave skin
Prurigo pigmentosa: The disorder is more
common in adults, with an onset in the spring and summer months. The
characteristic lesions are found on the trunk and neck, and present
as itchy red papules that occasionally coalesce to a reticular
pattern. Later they are superseded by a reticular hyperpigmentation.
The skin lesions and pruritus responds
dramatically to Dapsone.
This is the drug of choice for adults. The
recommended daily dose is 200mg. It is expected to clear the skin
lesion within a few days.
This type may show familial tendency with a
history of allergic reactions.
Hard, excoriated prurigo papule associated with
lichenifecation. Secondary infection is common.
Pustulation and pitted scars are common
manifestations due to the severe scratching and excoriation of the
Etiology of Prurigo
These are sometimes considered as predisposing
factors rather than real etiological factors:
External factors: insect bites
ectoparasites, allergic contactants. Physical factors such as
heat, cold and light.
Emotional stress and different psychogenic
Food and drug allergy.
Infections: internal septic focus such as chronic
tonsillitis and sinusitis.
Chronic atopic dermatitis
Local applications are of little value. Avoid
irritating substances, insect bites, avoid over heating or exposing
the skin to cold.
of the nodules with a
steroid such as triamcinolone is often helpful.
Antihistamines: Zyrtec10mg and Atarax, 25mg
and 100mg may help in relieving itching.
Tranquilizers: may be of great help
especially in emotionally disturbed individuals. Higher doses can be
given at night, where itching is more in some patients due to skin
heating especially in wintertime.
(Depot medrol or
Kenalog 40mg) can be given every 2-4 weeks.
Benoxaprofen have also been used with success
in some cases.
Thalidomide is probably the most effective
treatment, if it is not contra-indicated by the risk of pregnancy,
though there is always some risk of painful neuropathy.
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Prurigo pigmentosa successfully treated with minocycline. Br J
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Doyle JA, Connolly SM, Hunziker N et al.
Prurigo nodularis: a reappraisal of the clinical and histological
features. J Cutan Pathol 1979; 6: 392.
Hindson C, Lawlor F, Waks H. Treatment of
nodular prurigo with benoxaprofen. Br J Dermatol 1982; 107: 369.
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clinical review. J Am Acad Dermatol 1981; 4: 723-9.
Boss JM, Matthews CNA, Peachey RDG et al.
Speckled hyperpigmentation, palmo-plantar punctate keratoses and
childhood blistering. Br J Dermatol 1981; 105: 579-85.
Van der Broek H. Treatment of prurigo
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