Sweet’s syndrome (SS) is a rare, recurrent skin disease
characterized by painful papules, plaques, and nodules on the limbs,
face, and trunk, accompanied by fever and leukocytosis.
In the initial stage, SS may present as vesiculating papules;
varicella must be excluded at this stage.
Synonym Acute, febrile, neutrophilic
Age Infants, children, adults aging
from 30 to 60 years.
Etiology 50% idiopathic.
Possible hypersensitivity reaction to infection. In adults, SS can
be seen as an immunologic response to IBD, drugs, autoimmune disorders,
pregnancy, or malignancy (particularly AML).
SS is thought to represent a hypersensitivity reaction to an
infection (Streptococcal, Yersinia, atypical mycobacteria, CMV,
hepatitis, HIV, BCG vaccination), malignancy (acute myeloid leukemia,
transient myeloid proliferation, GU carcinoma, breast carcinoma,
colon carcinoma), autoimmune disease (Behcet’s, autoimmune
thyroiditis, sarcoidosis, dermatomyositis, SLE, rheumatoid arthritis,
relapsing polychondritis, Sjogren’s), IBD (ulcerative colitis),
or drug (G-CSF, furosemide, hydralazine, minocycline, and trimethoprim-sulfamethoxazole)
In cases of SS, upper respiratory tract infection or flulike
symptoms with high fevers precede the skin lesions by 1 to 3 weeks.
Then, there is a sudden appearance of tender and painful papules
and plaques on the face, neck, and limbs (usually spares torso),
associated with a leukocytosis and polyarthritis.
Type Papules, nodules, bullae (Fig.
Sweet’s syndrome Erythematous
plaques and nodules with central bullous changes on the legs of
Palpation Lesions are tender.
Shape Annular or arcuate.
Arrangement Single lesion or multiple
lesions, asymmetrically distributed.
Distribution Face, neck, and extremities.
arthralgias, arthritis, myalgias.
Ocular (50%) conjunctivitis,
episcleritis, limbal nodules, iridocyclitis.
Other Neutrophilic alveolitis,
multifocal sterile osteomyelitis (SAPHO syndrome), glomerulonephritis, hepatitis,
myositis, meningitis, encephalitis, pancreatitis, gastritis.
The differential diagnosis of SS includes erythema multiforme,
erythema nodosum, prevesicular herpes simplex infection, preulcerative
pyoderma gangrenosum, bowel-bypass syndrome, urticaria, serum sickness,
other vasculitides, SLE, and panniculitis.
Dermatopathology Edema and a dense,
perivascular infiltration with polymorphonuclear leukocytes in the
upper and mid-dermis without vasculitis.
Hematology Leukocytosis (>10000/ mm3),
increased ESR, C-reactive protein, α2-globulin fraction.
Untreated, SS lesions enlarge over a period of days or weeks,
and eventually resolve without scarring after 1 to 12 months. The
skin lesions exhibit an excellent response to systemic steroids,
usually resolving in days. Recurrences are seen in 50% of
patients, often in previously involved sites, especially in patients
with associated hematologic disorders.
If an infection is identified, proper antimicrobial therapy is
Both the skin lesions and systemic symptoms of SS respond dramatically
to steroids (prednisone or prednisolone). Solitary lesions can be
treated with topical steroids, and/or topical calcineurin inhibitors.
Other effective SS treatments include potassium iodide, clofazimine,
colchicine, indomethacin, naproxen, sulindac, cyclosporine, thalidomide,
α-interferon, and dapsone.
Pyoderma gangrenosum (PG) is a rapidly evolving, chronic, and
severely debilitating skin disease characterized by painful ulcers
with undermined borders and a purulent necrotic base. It occurs most
commonly in association with systemic disease, especially inflammatory
bowel disease or myeloproliferative disorders.
Synonyms Phagedenisme geometrique.
1. Ulcerative: Classic PG associated with IBD or arthritis.
2. Bullous: Atypical or bullous PG associated with AML, myelodysplasia,
and myeloproliferative disorders (CML).
3. Pustular: Sterile pustular eruption ±PG associated with IBD.
4. Superficial granulomatous: Localized vegetative lesion following
Age Infants, children, adults aging
from 20 to 50 years.
Etiology Idiopathic (25%–50%),
immunologic abnormality suspected.
Acute onset with painful hemorrhagic pustule or nodule either
de novo or following minimal trauma (pathergy), typically on the
An underlying immunologic abnormality in patients is suspected
since PG is often associated illnesses with such as large bowel
disease and small bowel disease, arthritis, paraproteinemia, multiple
myeloma, leukemia, active chronic hepatitis, and Behçet’s
Type Papule, pustule, nodule, ulcer
with undermined borders (Fig. 15-17).
Pyodema gangrenosum Necrotic
ulcers with undermined borders on the buttocks of an infant.
Shape Irregular or serpiginous.
Arrangement Usually solitary. May
form in clusters that coalesce.
Distribution Lower extremities
> genitals/ buttocks > abdomen > face.
Mucous Membranes Rarely, aphthae;
ulcers of oral mucosa and conjunctivae.
ulcerative colitis or Crohn’s syndrome.
Hematologic (25%) AML,
CML, hairy cell leukemia, myelodysplasia, monoclonal gammopathy.
The differential diagnosis of PG includes furuncle, carbuncle,
cellulitis, panniculitis, gangrene, ecthyma gangrenosum, atypical
mycobacterial infection, clostridial infection, deep mycoses, amebiasis,
bromoderma, pemphigus vegetans, stasis ulcers, and Wegener’s
Dermatopathology Nonspecific, nondiagnostic.
Neutrophilic inflammation, engorgement, and thrombosis of the small
and medium vessels. Necrosis, hemorrhage may be present.
Untreated, PG may last months to years. Lesions undergo necrosis
and ulceration can expose underlying tendons or muscles. Ulceration
may extend rapidly within a few days, or slowly and new ulcers may
appear as older lesions resolve. Reepithelialization begins at the
margins of the lesion and the lesions heal with atrophic scars.
PG is best managed by identification and treatment of any associated
underlying disease. For cutaneous lesions, management consists of
decreasing inflammation, reducing pain, and promoting healing.
Topical regimens for mild disease include gentle cleansing (0.25% acetic
acid soaks, whirlpool baths), wet dressings with potassium permanganate,
silver sulfadiazine cream, cromolyn sodium solution, nicotine patch,
topical or intralesional steroids, or tacrolimus.
For moderate disease or severe disease, oral steroids (prednisone,
prednisolone) are the most effective. Systemic cyclosporine or tacrolimus
can be used for PG refractory to steroids. Other treatment modalities
include oral antibiotics, colchicine, infliximab, dapsone, clofazimine,
potassium iodide, thalidomide, methotrexate, azathioprine, mycophenolate
mofetil, cyclophosphamide, chlorambucil, IVIG, and plasmapheresis.
Surgical debridement and excision of the ulcers should be avoided
because PG is subject to pathergy in 20% of cases.