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Rash with Target Lesions

What is Rash, target lesions?

A “target lesion” (also called a “bullseye” or “iris” lesion) is a raised skin rash that looks like a concentric circle – a dark centre surrounded by a paler ring and an outer reddish halo. The classic appearance resembles a shooting‑range target, hence the name. Target lesions are most often associated with immune‑mediated skin reactions, but they can also appear in infections, drug reactions, and systemic diseases. Recognising this pattern helps clinicians narrow the differential diagnosis and start appropriate care quickly.

Common Causes

The following conditions are the most frequent reasons a patient develops a rash with target‑shaped lesions. They are listed alphabetically; each can present with subtle variations in size, colour, and distribution.

• Erythema multiforme (EM) – a hypersensitivity reaction, often triggered by infections (particularly HSV‑1 or HSV‑2) or medications.
• Erythema multiforme major (Stevens‑Johnson syndrome, SJS) – a severe form of EM involving extensive skin detachment and mucosal involvement.
• Erythema multiforme minor – limited to skin with classic target lesions, without mucosal erosions.
• Mycoplasma pneumoniae infection – respiratory infection that can provoke atypical rashes, including target lesions.
• Drug reaction with eosinophilia and systemic symptoms (DRESS) – a delayed hypersensitivity reaction to certain drugs (e.g., anticonvulsants, sulfonamides).
• Fixed drug eruption (FDE) – recurs at the same site each time a specific drug is taken; lesions can become target‑shaped.
• Urticaria (hives) with bullous or target morphology – sometimes chronic urticaria can evolve into annular or target‑like plaques.
• Viral exanthems – infections such as measles, rubella, or parvovirus B19 can produce target‑type macules, especially in children.
• Syphilis (secondary stage) – the rash may be non‑specific but can occasionally form concentric lesions.
• Autoimmune diseases – lupus erythematosus or dermatomyositis may show target‑like papules on sun‑exposed skin.

Associated Symptoms

Target lesions rarely appear in isolation. Depending on the underlying cause, you may notice:

• Fever or chills
• Oral, ocular, or genital mucosal erosions (especially with SJS/TEN)
• Joint pain or swelling
• Throat soreness or dysphagia
• Respiratory symptoms – cough, shortness of breath (Mycoplasma pneumoniae)
• Gastrointestinal upset – nausea, abdominal pain
• Generalized fatigue or malaise
• Swollen lymph nodes
• Pruritus (itching) or burning sensation at the rash site

When to See a Doctor

Because a target‑lesion rash can herald serious systemic illness, promptly seek medical evaluation if you notice any of the following:

• Rapid spread of lesions over more than 10% of body surface area.
• Involvement of the lips, mouth, eyes, or genital mucosa.
• Fever higher than 101 °F (38.3 °C) accompanying the rash.
• Severe pain, blistering, or skin that sloughs off.
• Difficulty breathing, swallowing, or a sudden drop in blood pressure.
• Recent start of a new medication (especially antibiotics, antiepileptics, NSAIDs, or allopurinol) within the last 1‑3 weeks.
• History of HSV infection that recurs with a new rash.

Diagnosis

Evaluation typically follows a stepwise approach:

1. History taking – onset, progression, recent infections, drug exposures, travel, and associated systemic symptoms.
2. Physical examination – careful inspection of lesion morphology (size, colour, distribution) and checking for mucosal involvement.
3. Laboratory tests:
   • Complete blood count (CBC) – looks for eosinophilia (common in DRESS) or leukopenia.
   • Serum chemistries & liver function tests – assess organ involvement in severe drug reactions.
   • HSV PCR or culture from a vesicle if HSV‑related EM is suspected.
   • Mycoplasma serology or PCR when respiratory symptoms coexist.
   • Drug-specific lymphocyte activation tests (available at specialty centers).
   • RPR/VDRL for syphilis if risk factors present.
4. Skin biopsy – a 4‑mm punch biopsy can differentiate EM from other dermatoses; histology often shows necrotic keratinocytes and a lymphocytic infiltrate at the dermal‑epidermal junction.
5. Imaging (if indicated) – chest X‑ray for Mycoplasma pneumoniae or to rule out pulmonary involvement in severe drug reactions.

Treatment Options

Treatment is directed at the underlying cause plus symptomatic relief. The plan may be outpatient for mild EM, but moderate-to-severe cases (especially SJS/TEN) require hospitalization.

Medical Management

• Antiviral therapy – Acyclovir or valacyclovir for HSV‑triggered EM, given within 48 hours of lesion onset.
• Corticosteroids – Short courses of oral prednisone (0.5–1 mg/kg) for extensive EM; intravenous methylprednisolone in SJS/TEN is controversial but may be used in select centers.
• Immunomodulators – Cyclosporine or TNF‑α inhibitors (e.g., etanercept) have shown benefit in severe SJS/TEN in recent trials (NEJM 2020).
• Antibiotics – Only if a bacterial superinfection is documented. For Mycoplasma pneumoniae, macrolides (azithromycin) or doxycycline are first‑line.
• Drug withdrawal – Immediate cessation of the suspected offending medication is critical in DRESS, FDE, or SJS/TEN.
• Supportive care – Intravenous fluids, electrolyte management, and wound care akin to burn management for SJS/TEN.

Home & Symptomatic Care

• Cool compresses or soothing oatmeal baths to reduce itching.
• Over‑the‑counter antihistamines (cetirizine, loratadine) for pruritus.
• Topical corticosteroid ointments (hydrocortisone 1%) on limited, non‑mucosal lesions.
• Maintain good skin hygiene; avoid harsh soaps and tight clothing.
• Stay hydrated and rest; fever may be managed with acetaminophen (avoid NSAIDs if drug reaction suspected).

Prevention Tips

While not all target‑lesion rashes can be prevented, many strategies reduce risk:

• Practice good hand hygiene and avoid close contact with individuals who have active HSV lesions.
• When starting a high‑risk medication (e.g., allopurinol, sulfonamides, antiepileptics), discuss alternative options with your provider.
• Complete the full course of prescribed antibiotics to prevent bacterial resistance that can trigger hypersensitivity.
• Use sunscreen daily; UV exposure can exacerbate autoimmune rashes that may mimic target lesions.
• Keep a medication diary – note any new rash and the drug started within the prior 2‑3 weeks.
• Promptly treat respiratory infections (e.g., Mycoplasma) with appropriate antibiotics to lower the chance of a secondary rash.

Emergency Warning Signs

If any of the following develop, seek emergency care (ER or urgent care) immediately:

• Rapidly spreading blistering or skin sloughing covering >10% of body surface.
• Severe pain, especially in the mouth, eyes, or genitals, that interferes with eating, drinking, or vision.
• High fever (>103 °F / 39.4 °C) or persistent fever despite antipyretics.
• Difficulty breathing, swelling of the tongue or throat, or a feeling of “tightness” in the throat.
• Sudden drop in blood pressure, dizziness, or fainting (signs of shock).
• New onset of confusion, seizures, or severe headache.

Key Take‑aways

Rash with target lesions is a visual clue that the immune system is reacting to an infection, medication, or systemic disease. While many cases are mild and self‑limited, some progress to life‑threatening conditions such as Stevens‑Johnson syndrome or toxic epidermal necrolysis. Early recognition, removal of triggers, and appropriate medical treatment are essential. When in doubt, especially if mucosal surfaces are involved or systemic symptoms appear, consult a health professional promptly.

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References:

• Mayo Clinic. Erythema multiforme. https://www.mayoclinic.org
• Cleveland Clinic. Stevens‑Johnson syndrome and toxic epidermal necrolysis. https://my.clevelandclinic.org
• CDC. Mycoplasma pneumoniae infection. https://www.cdc.gov
• NIH. Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS). https://www.ncbi.nlm.nih.gov
• WHO. Management of severe cutaneous adverse reactions. 2023 guideline. https://www.who.int

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