Acne vulgaris

Acne vulgaris is a common skin disease that affects most individuals at some point in their lives. It is classified into different forms which vary in severity, lesion type, and localization, with the face commonly involved. The hallmark of acne are comedones, which can develop further into inflammatory papules, pustules, or even abscesses and nodules. Symptoms typically begin in early puberty and cease spontaneously during the third decade of life. There are multiple etiological factors: genetic predisposition, seborrhea, and hyperkeratosis are known to promote the development of acne. Topical and systemic treatment options are available to counteract inflammation and hyperkeratosis, as well as to help purify the skin.

• Prevalence: the most prevalent chronic skin condition in the US ^[1]
• Age of onset: typically by 11–12 years, with symptoms usually disappearing around 20–30 years of age ^[2]
• Sex: more common in males during adolescence; , but more common in women during adulthood

Epidemiological data refers to the US, unless otherwise specified.

• Genetic predisposition ^[3]
• Hormonal factors
  • ↑ Androgens during puberty → increased production of sebum by sebaceous glands
  • In women: menstrual cycle
• Follicular hyperkeratosis: Higher keratinocyte activity and decreased keratinocyte shedding in pilosebaceous units leads to the formation of comedones.
• Bacterial colonization with Cutibacterium acnes; (formerly known as Propionibacterium acnes) → inflammatory reactions with formation of papules, nodules, pustules, and/or cysts
• External factors
  • Climate
  • Drugs (e.g., anabolic steroids, progestin-only contraceptive pills, corticosteroids)
  • Food ^[4]

• Localization: common in areas with sebaceous glands (predilection sites: face, shoulders, upper chest, and back)
• Primary lesions
  • Non-inflammatory: comedonal acne
    • Closed comedones (“whiteheads”): closed small round lesions that contain whitish material (sebum and shed keratin)
    • Open comedones (“blackheads”): dark, open portion of sebaceous material
  • Inflammatory: affected areas are red and can be painful
    • Papular/pustular acne: papules, pustules that arise from comedones
    • Nodular acne (> 5 mm in diameter)
      • Commonly the back and neck
      • Severe form: acne conglobata that is associated with cysts and abscesses
• Secondary lesions: : postinflammatory erythema, hyperpigmentation, and scarring

References:^[5]

Hidradenitis suppurativa ^[6]

• Definition: chronic skin condition characterized by painful lumps located under the skin that are thought to be caused by a blockage of hair follicles ^[7][8]
• Epidemiology ^[6]
  • Prevalence: 0.05–0.2%
  • Average age of onset: 20–30 years
• Etiology
  • The exact cause is still unknown.
  • Most likely an interaction of genetic (e.g., dysregulation of signaling pathways that promote follicular hyperkeratinization and elevated levels of proinflammatory cytokines) with environmental (e.g., bacterial colonization of hair follicles) factors and hormonal imbalances
• Risk factors: obesity, smoking, family history, female sex, certain medications (e.g., lithium, levonorgestrel) ^[9]
• Pathophysiology: blockage of hair follicle → dilation and rupture → spilling of follicular contents into dermis → inflammatory response → abscess formation and destruction of the pilosebaceous unit
• Clinical features
  • Localized in folded skin areas containing apocrine glands (most commonly the axillae, groin, inner thigh, perineal and perianal areas)
  • The first lesion is usually a solitary painful inflammatory nodule that progresses to an abscess that may open or regress spontaneously.
  • Sinus tracts may form between multiple recurrent nodules and drain foul-smelling, seropurulent discharge.
  • Development of open; and closed comedones
  • Scarring ranges from small, individual acneiform scars to thick scarred plaques that affect larger areas of skin
• Diagnosis: clinical
• Differential diagnosis: folliculitis, acne vulgaris, Crohn disease, granuloma inguinale
• Management
  • General
    • Patient education, psychological support
    • Wound management and skin care (e.g., use of antiseptic washes)
    • Reduction of body weight, smoking cessation
  • Conservative
    • Antibiotics (e.g., topical clindamycin, oral tetracyclines)
    • Oral retinoids (e.g., isotretinoin)
    • Biologics (adalimumab, infliximab)
  • Surgical (for severe cases that are refractory to medication): incision, surgical removal with skin grafts
• Complications
  • Lymphedema as a result of lymphatic obstruction due to excessive scarring
  • Depression and/or social isolation (e.g., due to the overall reduced quality of life, spontaneous malodorous discharge)
  • Superinfection
• Prognosis: chronic disease with a high rate of recurrence

Neonatal cephalic pustulosis ^[10]

• Age of onset: first few weeks of life
• Clinical presentation: papulopustular rash without comedones
• Treatment
  • Self-limited disease ; no specific treatment
  • Topical treatment options include ketoconazole and hydrocortisone

Infantile acne ^[10]

• Age of onset: ≥ 3 months
• Clinical presentation: papulopustular rash, closed comedones, and sometimes formation of nodules (more common in boys)
• Treatment: benzoyl peroxide , possibly in combination with erythromycin; in contrast to neonatal acne, treatment is indicated to avoid scarring

Acne fulminans ^[11]

• Definition: a rare, severe form of acne that is characterized by painful ulcerative skin lesions and systemic inflammatory symptoms
• Epidemiology
  • Rare disease (approx. 200 documented cases)
  • Age of onset: 13–22 years of age
  • ♂ > ♀ (3:1)
  • Mainly individuals of northern European descent
• Etiology
  • Adverse effect of isotretinoin (most common)
  • Idiopathic
• Clinical features
  • Primary lesions
    • Acute onset
    • Large, painful nodules, plaques, and ulcers with hemorrhagic crusts
    • Most commonly located on the trunk
  • Systemic manifestations
    • Fever
    • Myalgia
    • Weight loss
    • Arthralgia, arthritis
    • Rarely hepatosplenomegaly, erythema nodosum, septic osteomyelitis
• Diagnostics
  • ↑ CRP, ↑ ESR
  • Leukocytosis, thrombocytosis, anemia
  • ↑ Liver enzymes
• Treatment ^[12]
  • Discontinue isotretinoin
  • Initial monotherapy with systemic corticosteroids
  • Subsequent combination therapy with oral corticosteroids and isotretinoin
  • Treatment-resistant cases: cyclosporine, biologics (e.g., anakinra, secukinumab, ustekinumab), or dapsone

Acne treatment ^[13]

Therapy is particularly important for patients with inflammatory acne to prevent complications such as scarring.

Retinoids ^[5][13]

• Main substance: isotretinoin (vitamin A derivative) given systemically
• Indication: : in moderate to severe acne
• Mechanism of action: Retinoids normalize keratinization by inhibiting and modulating keratinocytes → ↓ sebum production
• Contraindications
  • Pregnancy, women of childbearing age without contraception: strong teratogenic effects
  • Liver disease
  • Simultaneous tetracycline treatment
• Precautions (in all females of childbearing potential) ^[14]
  • 1 month before initiating therapy:
    1. A serum/urine pregnancy test
    2. Two methods of contraception (oral contraceptive therapy + barrier contraception / IUD)
  • During therapy: monthly pregnancy test and continuous use of two methods of contraception
  • After completing therapy:
    1. Continue two methods of contraception for 1 month
    2. A pregnancy test at the end of 1 month
• Side effects
  • Dry skin, xerostomia, cheilitis, pruritus
  • Headaches, arthralgias, alopecia, fatigue
  • Congenital craniofacial anomalies (e.g., dysmorphisms, microtia, microphthalmia, cleft palate)
  • Pericardial effusion, atrial tachycardia, congenital heart disease (e.g., great vessel anomalies)
  • Thymic hypoplasia, PTH deficiency
  • Congenital CNS defects (e.g., hydrocephalus, cortical blindness, microcephaly), idiopathic intracranial hypertension
  • Laboratory test abnormalities
    • Blood disorders (e.g., anemia)
    • ↑ Triglycerides, ↓ HDL, ↑ glucose
    • ↑ AST, ↑ ALT

Retinoid therapy should be discontinued at the latest one month before planned conception.