Hives Are Not a Common Manifestation of Streptococcal Infection
Urticaria (hives) is not typically associated with streptococcal pharyngitis or other strep infections, though nonspecific rashes can occasionally occur as immune-mediated reactions to various infections.
Understanding Urticaria and Strep Infections
Primary Causes of Acute Urticaria
The most common triggers for acute urticaria in clinical practice include:
- Viral infections are the predominant infectious cause of acute urticaria in children and adults, not bacterial infections like strep 1, 2
- Allergic reactions to foods, drugs, and contact with chemicals or irritants are more frequently implicated than bacterial infections 1
- Idiopathic causes account for approximately 50% of acute urticaria cases where no specific trigger can be identified 2
Streptococcal Infections and Skin Manifestations
When streptococcal infections do cause skin findings, they typically present as:
- Cellulitis or erysipelas with erythema, warmth, and edema rather than urticarial wheals 3
- Petechiae and ecchymoses may develop on inflamed skin in severe streptococcal infections, but these are distinct from the transient, pruritic wheals characteristic of urticaria 3
Clinical Distinction: True Urticaria vs. Other Rashes
Urticaria has specific defining features:
- Erythematous, edematous, pruritic plaques that are transient 4
- Individual lesions resolve within 2-24 hours without leaving a trace 4, 1
- Wheals that blanch completely with pressure 5
This differs from infection-related rashes that:
- Persist and evolve over days rather than hours 5
- May have fixed patterns or target-like morphology (as in erythema multiforme) 5
- Often accompany systemic symptoms like fever and lymphadenitis 3
Clinical Pitfalls to Avoid
Do not confuse urticaria with:
- Erythema multiforme, which can follow various infections (including mycoplasma and herpes simplex) and presents with target lesions that persist for days, not the transient wheals of urticaria 3, 5
- Nonspecific viral exanthems, which are far more common with infections than true urticaria 1
- Cellulitis from streptococcal infection, which presents with localized erythema and warmth rather than migratory wheals 3
Bottom Line for Clinical Practice
If a patient presents with both strep infection and urticaria:
- Consider these separate, coincidental conditions rather than causally related 1, 2
- Look for alternative urticaria triggers such as medications used to treat the strep infection (antibiotics are common urticaria triggers) 1, 2
- Viral co-infection is more likely to cause urticaria than the streptococcal infection itself 1