Page 397 - Medicine and Surgery

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Chapter 9: Bullous disorders 393

Lichen simplex chronicus Aetiology/pathophysiology
(neurodermatitis) Patients have IgG autoantibodies against desmoglein
(dsg), which are adhesion molecules that hold epi-
Definition
dermal cells together. The absence of epidermal ad-
Lichen simplex chronicus or nodular prurigo refers to
hesion results in intraepidermal blisters. The genetic
acutaneous response to rubbing or scratching normal
predisposition to develop these autoantibodies may
skin.
be HLA related. Paraneoplastic pemphigus is associ-
ated with lymphoreticular malignancies such as non-
Aetiology Hodgkin’s lymphoma, chronic lymphocytic leukaemia
More common in Asian, African and Oriental patients and Waldenstr¨ om’s macroglobulinaemia. Drugs such as
and is associated with atopic tendency. penicillamine, penicillin or captopril may induce pem-
phigus or unmask latent disease.
Clinical features
Following intense itching and recurrent scratching of Clinical features
a patch of skin, lichen simplex chronicus presents as a Pemphigus vulgaris presents with flaccid painful blis-
single plaque often on the lower leg, neck or the per- ters and erosions often initially in the oropharynx and
ineum. Nodular prurigo presents as multiple itchy nod- then the scalp, face, groin and chest. The blisters rup-
ules, which are more diffusely distributed. ture easily, so often only erosions are seen. Sliding
pressure easily dislodges the epidermis at the edge of
Management blister (Nikolsky sign).
Lesionsareoftenrefractorytotreatmentalthoughtopical Pemphigus foliaceus causes a more superficial epider-
steroids, tar bandages and phototherapy are tried. mal weakness causing erosions rather than blisters.
Patients present with erythema, and crusting on the
face and scalp, chest and back without involvement of
Bullous disorders the mucous membrane.
Paraneoplastic pemphigus causes severe disease in-

volving both the skin and mucosal membranes.
Pemphigus
Complications
Definition
Pemphigus is a group of severe, chronic, autoimmune, There may be extensive fluid and protein loss and sec-
ondary infection particularly due to the immunosup-
superficial blistering diseases of the mucous membranes
pressive nature of medications.
and skin. The commonest form is pemphigus vulgaris.
Two other forms have been described: pemphigus foli-
aceus and paraneoplastic pemphigus. Investigations
Diagnosed by biopsy of an early, small blister or the edge
ofnewerosion.Lightmicroscopyanddirectimmunoflu-
Incidence
orescence for IgG deposition at epidermal cell junctions.
Uncommon
Identification of anti-dsg autoantibodies may be useful.
Age
Management
Peaks in the middle-aged and elderly.
High-dose systemic corticosteroids tailored dependent
on clinical response. If control cannot be maintained on
Sex low-dose steroids, immunosuppressive agents are used
M = F as steroid sparing agents including azathioprine, cy-
clophosphamide and methotrexate. Plasmapheresis and
Geography intravenous immunoglobulin have been used in refrac-
Increased incidence in Ashkenazi Jews. tory cases.