Oil Acne

Oil acne is a follicular eruption of comedones and pustules on skin repeatedly contaminated by insoluble cutting oils, lubricating oils, petroleum products or heavy oils. It is a mechanical and chemical follicular occlusion disease.

Exposure. Machinists, lathe and milling operators, mechanics, oil rig and refinery workers, and people whose clothing is soaked in oil.

Epidemiology. One of the commonest occupational skin diseases in engineering. Straight oils cause more disease than water mixed fluids.

Distribution. Forearms, thighs and other covered areas in contact with oil soaked clothing, rather than the face and trunk.

Course. It resolves over weeks to months after exposure is controlled. Chronic oil exposure raises the risk of skin cancer of the exposed areas.

Pathophysiology.

Oil film blocks follicular openings and carries particles into hair follicles, causing hyperkeratosis and dilatation of follicular orifices.

Follicular rupture and secondary bacterial colonisation produce inflammatory papules and pustules.

• Black comedones, follicular papules and pustules on the dorsal forearms, thighs and other oil contact sites.
• Dilated pores with plugging and sometimes boils.
• Little itch unless dermatitis coexists.

Red flags.

• Spreading erythema, abscess or fever (secondary infection).
• Warty, ulcerated or non-healing lesion, especially on the scrotum or forearms (squamous cell carcinoma).

• Exposure history: oil type, soaking of clothing, washing practice and effect of time off.
• Examination of distribution and follicular plugging.
• Swab for pustules; patch testing if dermatitis is present.
• Biopsy of any suspicious lesion.

Differential diagnosis. Acne vulgaris, folliculitis from other causes, chloracne, keratosis pilaris, tinea, irritant or allergic contact dermatitis, drug induced acneiform eruption.

• Control contact: enclose machines, splash guards, remove oil soaked clothing promptly, wash overalls frequently, avoid wiping hands on clothing, and wash skin after the shift with mild soap, not solvents.
• Barrier cream applied before work as an adjunct, and nitrile gloves with long cuffs.
• Adapalene 0.1% gel topically once daily at night to affected areas. Maximum one thin application daily. Monitor irritation and photosensitivity. Avoid in pregnancy; no renal or hepatic adjustment.
• Benzoyl peroxide 5% gel topically once daily in the morning for up to 12 weeks. Maximum twice daily. Monitor irritation and bleaching of fabrics. No renal adjustment.
• Doxycycline 100 mg orally once daily with food and a full glass of water for up to 12 weeks for inflammatory disease. Maximum 100 mg daily. Monitor photosensitivity and oesophagitis. Avoid in pregnancy, breastfeeding and under 12 years; no renal adjustment; caution in hepatic impairment.
• Secondary bacterial infection: flucloxacillin 500 mg orally four times daily for 7 days. Maximum 1 g four times daily in severe infection. Monitor liver function if therapy exceeds 14 days. Reduce dose when eGFR is under 10; avoid in penicillin allergy or prior flucloxacillin related jaundice, and use a macrolide chosen by swab sensitivity instead.
• Suspicious skin lesion: biopsy and excision.

Monitoring. Review at 4 to 6 weeks, then every 6 months; yearly skin examination in long term oil workers.

Referral and escalation. Dermatology for persistent disease or any suspicious lesion; occupational physician for process and clothing changes; notification and compensation where required.

Special groups. Pregnancy: avoid retinoids and tetracyclines.