Acneiform drug eruption

Definition

Acneiform drug eruption is an acne-like follicular skin reaction triggered by drugs. Unlike acne vulgaris, it is typically monomorphic, may occur outside the seborrhoeic areas and at an atypical age, and is temporally linked to a newly started drug.

Occurrence & epidemiology

Follicular drug eruptions are estimated to account for about 1% of all drug reactions; men are affected more often than women.

Aetiopathogenesis

The main triggering drug groups are:

• glucocorticoids, androgens and anabolic agents
• antituberculosis drugs and anticonvulsants
• halogen compounds (iodides, bromides)
• immunosuppressants and immunomodulators
• targeted cancer drugs, with the highest risk for agents directed against the EGF receptor

Pathogenetically, altered sebum composition, a shifted follicular microbiome (Cutibacterium acnes) and neutrophilic follicular inflammation act together.

Clinical features

• Onset usually weeks to months after the triggering drug is started, often as early as 1–3 weeks with targeted cancer drugs.
• Monomorphic inflammatory follicular papules and pustules; comedones are often absent.
• Mainly seborrhoeic areas (face, scalp, upper trunk), sometimes also the upper arms and atypical sites up to the palms and soles.
• Accompanied by burning, itching, seborrhoea; usually no systemic involvement.
• With EGFR blockade, additionally paronychia, disturbed hair growth, itching and dry skin.

Histology

Usually a superficial, neutrophil-predominant suppurative folliculitis with dilated infundibula and focal rupture of the follicular epithelium; comedones are frequently absent.

Diagnosis

• Clinical diagnosis: monomorphic papulopustules with a temporal link to a new drug (drug history).
• Distinction from acne vulgaris (polymorphic, with comedones), rosacea, perioral dermatitis, Malassezia folliculitis and AGEP (abrupt onset of non-follicular pustules, often fever).

Differential diagnoses

• Acne vulgaris
• Rosacea
• Malassezia (Pityrosporum) folliculitis
• Urticaria
• Airborne contact dermatitis
• AGEP (acute generalized exanthematous pustulosis)
• Miliaria Pustulosa

Keep learning in the app

References (selection)

1. PubMed: Acneiform drug eruptions – update on pathophysiology and culprit drugs (PMID 41810246)
2. PubMed: Drug-induced acneiform eruption (PMID 21668032)
3. DermNet: Steroid acne

Cross-references