Erythema nodosum

general medicine
dermatology

1. APPROACH TO
ERYTHEMA NODOSUM
DR A P Naveen Kumar
Chief Specialist ( General Medicine )
Visakha Steel General Hospital
Visakhapatnam

2. INTRODUCTION

4. PATHOPHYSIOLOGY
Delayed hypersensitivity reaction to a variety of
antigens
CIC have not been found in idiopathic or
uncomplicated cases
IBD – may show immune complexes

5. HISTOLOGIC FINDINGS
Septal panniculitis -septal
edema and lymphohistiocytic
infiltrate
Miescher’s microgranulomas -
clusters of macrophages
around small vessels or a slit-
like space
Lymphohistiocytic infiltrate
Granuloma and lipogranuloma
formation

6. CLINICAL FEATURES
Erythema nodosum usually starts
with flu-like symptoms of fever and
bodyaches
 Arthralgia may precede the
eruptive phase
Red tender nodules usually on the
anterior surface of legs-shins
Other areas- arms, trunk and face
Lesions borders are poorly
defined and vary from
2 cm to 10 cm
1 st week - tense, hard,
red and painful

7. 2nd week - fluctuate and attain a
yellowish hue, resembling a bruise
Do not suppurate or ulcerate
Individual lesions usually last for 2
weeks but occasionally new lesions
appear up to 3–6 weeks
Lesions disappear as the overlying
skin desquamates
Joint tenderness and morning stiffness
may occur.
No destructive changes occur.
Synovial fluid is acellular and
rheumatoid factor (RF) negative

9. INFECTIONS
Streptococcal
Tuberculosis
Deep fungal infections
Coccidiodomycosis (4–10%)
Yersinia enterocolitis
Cryptococcus
Rickettsia
Histoplasmosis
Blastomycosis
Infectious mononucleosis
Mycoplasma
Salmonella
Campylobacter
Lymphogranuloma venereum
Parasitic diseases

10. DRUGS
Sulfonamides
OCP
Sulfonylureas
Gold
Penicillins
Iodides
Bromides
Phenytoin
Minocycline

11. SYSTEMIC DISEASES
Sarcoidosis (10–22%)
Inflammatory bowel disease
Leprosy
Pregnancy
Behçet disease
NHL
AML

12. STREPTOCOCCAL PHARYNGITIS
Beta-hemolytic streptococcal infections- most common
44% - adults and 48% - in children
 EN eruptions-2–3 weeks after an episode of streptococcal
pharyngitis
Should have throat culture evaluation for group A strep.,
as well as strep. antistreptolysin O (ASO) titers or
polymerase chain reaction (PCR) assays, or both
 ASO titers should be taken at the time of diagnosis and
then again within 4 weeks to assess for strep. infection

14. TUBERCULOSIS AND
MYCOBACTERIAL INFECTIONS
Erythema nodosum may occur with primary TB
 All patients with EN should be stratified by risk for TB
exposure
 Antitubercular therapy (ATT) should be initiated for EN in
patients with positive Mantoux skin test reactions

Culture identification from primary sites identifying an
atypical nontuberculous mycobacterium as a cause of EN.

16. Nodule
Multiple
granulomas
Granuloma
Epitheloid granuloma with necrosis

18. LABORATORY DIAGNOSIS
Careful history, physical examination and drug history
Prior diarrheal illness, URTI and any endemic infections
Throat culture—rules out streptococcal infection
CBC and ESR
Antistreptolysin O (ASO)/DNase titer at 2 weeks and 4 weeks interval
Stool examination.
Chest X-ray (CXR)— purified protein derivative (PPD) to rule out
Koch’s, unilateral hilar lymph nodes—Infections and malignancy
CXR to rule out sarcoid—bilateral hilar lymph nodes
Biopsy the lesion to rule out vasculitis—Collagen vascular disease.

19. DIFFERENTIAL DIAGNOSIS
Lupus panniculitis—present in fatty areas such as
buttocks, posterior arms and leave scars
Tuberculous erythema induratum—usually ulcerate
Erythema nodosum leprosum
Acute urticaria—itching is intense
Nodular vasculitis-PAN—look for fixed livedo reticularis
Sarcoidosis
Superficial thrombophlebitis—linear tender streaks
Erysipelas
Filarial lymphadenitis
Insect bites.

20. SARCOID

21. IBD

22. APLA
Lupus anticoagulant positive
Anti Cardiolipin antibodies -positive

25. CHRONIC ERYTHEMA NODOSUM
Chronic EN is a condition in which the lesions pop up
elsewhere for a period of weeks to months
In most of the cases a cause is elusive
 TB should be considered in our settings and a trial ATT may
be given
 Intense investigations to rule out sarcoid, IBD and collagen
vascular disease (CVD) should be done
 Rare association- Takayasu arteritis, vitamin B12 deficiency
and Ehlers Danlos has been reported.

26. RECURRENT EN

27. THERAPEUTIC LADDER FOR EN
Discontinue possible causative medications
Treatment of underlying infectious diseases mainly
streptococcal and TB
Bed rest and leg elevation and nonsteroidal anti-
inflammatory drugs (NSAIDs) (aspirin, ibuprofen,
indomethacin, naproxen)
Potassium iodide—saturated solution of potassium
iodide-5–15 drops three times a day. Mechanism of
action is exactly not known
Colchicine in the setting of Behçet’s disease

28. Various treatments for IBD like systemic steroids, HCQS, MMF,
cyclosporine, thalidomide, infliximab and etanercept are effective in
managing the underlying EN
 Paradoxically both infliximab and etanercept have been reported to
produce EN as a cutaneous side effect.
NSAID are to be avoided in IBD as they aggravate the disease
Systemic steroids - relatively safe therapeutic option if underlying
infection, risk of bacterial dissemination or sepsis and malignancy has
been excluded by a thorough evaluation
 A general rule is 1 mg/kg (body weight)/day.

29. USE OF POTASSIUM IODIDE
Saturated solution of potassium iodide 1,000 mg/mL
Droppers - for calibrations: 0.3 mL (300 mg),0.6 mL ( 600 mg)
In adults and older children, common dose = 300 mg TDS with starting
dose = 150–300 mg TDS
Saturated solution of potassium iodide (SSKI)- bitter taste – water or
fruit juice
Crystallization in cold - rewarming and shaking
Discard if solution turns yellow-brown
Side effects: Acute—nausea, eructations, excessive salivation,
urticaria, angioedema, small vessel vasculitis
Chronic—enlargement of salivary and lacrimal glands, acneiform
eruptions, iododerma, hypothyroidism, hyperkalemia and occasionally
hyperthyroidism

30. PROGNOSIS
Erythema nodosum prognosis is excellent
The lesions resolve without any adverse reactions
in most cases
Few cases are recurrent and refractory for which
an underlying cause is to be ascertained and
treated accordingly
Some of the idiopathic cases respond to
colchicine/dapsone on prolonged treatment.

31. CONCLUSIONS
Erythema nodosum is an acute panniculitis
presenting as subcutaneous nodules most
commonly due to infections and responds well to
treatment
Chronic nodules need to be investigated
thoroughly and treated accordingly.

32. ACKNOWLEDGEMENTS
Dr Mala Saranathan ,Dermatologist
Dr G Srihari , Dermatologist
Dr M Srinivas , Pathologist
Dr M Santipriya , Pathologist