Makindo Medical Notes

Related Subjects: | Nikolsky's sign | Koebner phenomenon | Erythema Multiforme | Pyoderma gangrenosum | Erythema Nodosum | Dermatitis Herpetiformis | Lichen Planus | Acanthosis Nigricans | Acne Rosacea | Acne Vulgaris | Alopecia | Vitiligo | Urticaria | Basal Cell Carcinoma | Malignant Melanoma | Squamous Cell Carcinoma | Mycosis Fungoides (Sezary Syndrome) | Xeroderma Pigmentosum | Bullous Pemphigoid | Pemphigus Vulgaris | Seborrheic Dermatitis | Pityriasis/Tinea Versicolor Infections | Pityriasis Rosea | Scabies | Dermatomyositis | Toxic Epidermal Necrolysis | Stevens-Johnson Syndrome | Atopic Eczema/Atopic Dermatitis | Psoriasis

Erythema multiforme is a skin reaction that can be triggered by infections or medications. It is typically mild and resolves within a few weeks, but in some cases, it can progress to Stevens-Johnson syndrome.

About

• Erythematous skin rash with various potential causes.

Clinical Features

• Characterized by target lesions—red rings with a pale center and a central red dot.
• Systemic symptoms include malaise, fever, and general discomfort.
• Mucous membranes are usually unaffected but should be inspected.
• Check for lesions in the mouth, throat, or genitals, which can be painful.
• May be associated with a current or recent HSV (1-3 weeks prior) infection.
• A chest infection may indicate Mycoplasma pneumoniae infection.
• Can present with sore joints, red eyes, and photophobia.
• Useful to mark lesions to track spread or resolution.

Typical Target Lesion

• Tender target lesion with a red ring, pale center, and central red dot.

Causes

• Viruses: HSV 1/2, hepatitis B, Epstein-Barr virus (EBV), enteroviruses.
• Bacterial agents: Group A Streptococcus, Mycoplasma pneumoniae, eosinia.
• Mycobacterium tuberculosis, histoplasma, Coccidioides.
• Medications: sulpha derivatives, NSAIDs, Penicillin, isoniazid, tetracycline.
• Other: Connective tissue diseases, pregnancy, radiation therapy, malignancy (Leukaemia, Lymphoma).

Differentials

• Urticaria

Investigations

• FBC, U&E, LFT. Raised CRP may be seen.
• Pregnancy test if applicable.
• CXR may show changes if pneumonia or TB is suspected.
• Biopsy may reveal dermal edema and lymphocytic infiltrates with keratinocyte degeneration along the dermo-epidermal junction.

Management

• Discontinue any causative drugs.
• If Mycoplasma pneumoniae is suspected, antibiotics are indicated.
• Mild Cases:
  • Supportive treatment, including antihistamines for itching.
  • Aciclovir PO if signs of HSV infection are present.
  • Topical steroids may be prescribed and monitored.
• Severe Cases:
  • Systemic steroids may be required; azathioprine in severe cases.
  • Mucosal involvement may lead to difficulty eating and drinking.
  • IV Aciclovir may be needed if HSV is suspected.
  • Supportive care with IV fluids and nutrition for severe cases requiring hospitalization.
  • Ophthalmology and dermatology reviews are essential.