Can Wegovy Cause Rash?
Yes, Wegovy (semaglutide) can cause rash, though it is not among the most common adverse effects; when a mild localized erythematous or pruritic rash occurs, discontinue the medication and initiate topical corticosteroids with oral antihistamines, monitoring for resolution within 1 month.
Incidence and Clinical Presentation
Dermal hypersensitivity reactions to semaglutide have been documented in case reports, presenting as eruptions on the trunk, extremities, chest, back, and abdomen that develop weeks to months after initiation 1.
Histopathologic examination reveals subepidermal blistering with eosinophils or perivascular inflammatory infiltrates with eosinophils, confirming drug hypersensitivity as the underlying mechanism 1.
The rash typically appears after 3 weeks to 3 months of treatment, though onset timing varies considerably between patients 1.
Allodynia (skin tenderness to touch) has been reported in association with semaglutide dose escalation, particularly at the 2.4 mg weekly dose used for obesity management, representing a distinct cutaneous adverse effect 2.
Management Algorithm
For Mild Localized Rash (Erythema or Pruritus Without Systemic Symptoms)
Immediately discontinue semaglutide to prevent progression to more severe hypersensitivity reactions 1.
Initiate topical corticosteroids (moderate-to-high potency) applied twice daily to affected areas, combined with oral H1-antihistamines for pruritus control 3.
Monitor weekly for symptom resolution; both documented cases showed complete resolution within 1 month of drug discontinuation 1.
Do not rechallenge with semaglutide once hypersensitivity is confirmed, as recurrence is likely and may be more severe 1.
For Severe or Progressive Rash
Discontinue semaglutide immediately if any signs of bullous eruption, exfoliative dermatitis, or mucosal involvement develop 3.
Initiate systemic corticosteroids (prednisone 1 mg/kg daily) with gradual taper over 4–6 weeks for severe reactions 3.
Refer to dermatology urgently if blistering, widespread erythema, or systemic symptoms (fever, lymphadenopathy) are present 3.
For Allodynia Without Visible Rash
Two management options exist based on patient preference and therapeutic need 2:
Gabapentin or pregabalin may be considered for symptomatic relief of neuropathic-type pain if continuation is elected 3.
Key Clinical Distinctions
Semaglutide-induced rash differs fundamentally from injection-site reactions, which are localized, transient, and do not require drug discontinuation 4.
The hypersensitivity pattern is distinct from the acneiform rash seen with EGFR inhibitors, which presents with follicular papules and pustules in seborrheic distribution without eosinophilic infiltration 3.
Gastrointestinal adverse effects (nausea, constipation, vomiting) are the most common side effects of semaglutide, occurring in a dose-dependent manner, but do not predict or correlate with dermatologic reactions 3, 4.
Critical Pitfalls to Avoid
Do not attribute all cutaneous symptoms to injection technique or site reactions; true hypersensitivity requires systemic drug discontinuation, not simply rotating injection sites 1.
Do not attempt dose reduction as a management strategy for confirmed hypersensitivity rash; the reaction is immunologically mediated and will persist or worsen with continued exposure 1.
Do not switch to oral semaglutide or other GLP-1 receptor agonists without dermatology consultation, as cross-reactivity within the GLP-1 RA class has been documented with dulaglutide and liraglutide 1.
Do not confuse allodynia with peripheral neuropathy from diabetes; semaglutide-associated allodynia has a clear temporal relationship to dose escalation and resolves with drug discontinuation 2.
Alternative Weight Management Options
If semaglutide must be discontinued due to rash, consider alternative anti-obesity pharmacotherapy including naltrexone/bupropion ER (5–9% weight loss over 56 weeks) or orlistat (4.65 kg weight loss over 24 weeks), both with established cardiovascular safety profiles 3.
Bariatric surgery remains the most effective long-term obesity treatment for patients with BMI ≥35 kg/m² and should be discussed when pharmacotherapy fails or is contraindicated 3.