What is the diagnosis and treatment for a patient with black spots all over their body?

Diagnosis: Congenital Melanocytic Nevi vs. Vitiligo

The term "black spots all over the body" most likely describes either congenital melanocytic nevi (CMN) if the patient is an infant/child with brown-black lesions present from birth, or vitiligo if the patient has white depigmented patches that appear black against darker skin. The critical first step is determining whether these are hyperpigmented (dark) or hypopigmented (white) lesions, as this fundamentally changes the diagnosis and management.

Differential Diagnosis Approach

If Lesions Are Dark/Hyperpigmented (Brown-Black):

Suspect Congenital Melanocytic Nevi (CMN) - these present as shades of brown and black within macules, papules, patches, or plaques, often with hypertrichosis (excess hair growth) and color variation 1.

Key Diagnostic Features:

• Timing: Present at birth or appearing in early infancy 1
• Appearance: Brown-black lesions with possible nodules, red-pink amelanotic papules, or blue-gray patches depending on subtype 1
• Distribution: Can be single or multiple ("satellite nevi"), with giant CMN defined as >40 cm projected adult size 1

Risk Stratification for CMN:

• Melanoma risk: 0.7-1.7% overall in patients with CMN, but increases to 8% in patients with multiple CMN and giant CMN >60 cm 1
• Highest risk factors: Projected adult size >40 cm, numerous satellite nevi, trunk location, and multiple medium CMN 1
• Neural melanosis risk: Patients with multiple CMN (historically >20) are at highest risk 1

If Lesions Are White/Hypopigmented:

Suspect Vitiligo - an acquired depigmentation disorder with well-defined white patches, often symmetrically distributed 1, 2.

Key Diagnostic Features:

• Timing: Acquired (not present at birth), mean age of onset 26.2 years but can occur from early infancy to old age 3
• Appearance: White depigmented macules and patches with no surface change, no redness (except occasionally at advancing edge) 1
• Distribution patterns:
  • Vitiligo vulgaris (50.8%): Symmetrical distribution 3
  • Focal non-segmental (23%) 3
  • Acrofacial (12.3%): Fingers, wrists, face 3
  • Segmental: Unilateral, following dermatome or Blaschko's lines 1
• Common initial sites: Head and neck (41.8%), lower limbs (18%) 3

Diagnostic Confirmation:

• Wood's light examination: Useful to identify depigmented areas not visible to naked eye, especially in pale skin 1
• Clinical diagnosis: Straightforward in classical symmetrical presentations; atypical cases require dermatologist assessment 1

Management Based on Diagnosis

For Congenital Melanocytic Nevi:

Immediate Assessment:

• Complete skin examination to count and measure all CMN 1
• Calculate projected adult size for risk stratification 1
• MRI of brain and spine if patient has multiple CMN (>1 CMN per recent proposals, though not universally accepted) or giant CMN >40 cm to screen for neural melanosis 1

Surveillance Strategy:

• Regular skin examinations for changes suggesting malignant transformation 1
• Monitor for symptoms of neural melanosis: seizures, headaches, rapidly enlarging head circumference, spinal cord compression symptoms 1
• Watch for melanoma warning signs: Progressive size change, nodule development, ulceration 4, 5

Skin Care Management:

• Pruritus control: Bland, thick emollients (creams/ointments with minimal fragrances) for chronic management; low-to-mid potency topical corticosteroids twice daily for acute eczematous flares 1
• Bathing: Water alone or nonsoap cleanser 2-3 times weekly, followed by bland emollient application 1
• Gentle handling: CMN may have increased fragility with ulcerations and bleeding from minimal trauma 1

Surgical Considerations:

• Excision indications: High-risk lesions (giant CMN, multiple CMN), cosmetic concerns, or suspicious changes 1
• Biopsy technique: Full excision with 2 mm margin using surgical knife (not laser/electrocoagulation) to preserve tissue for histopathology 4

For Vitiligo:

Initial Management Approach:

For Children (<18 years):

• First-line: Potent or very potent topical steroid for trial period of no more than 2 months (skin atrophy is common side-effect) 1
• Alternative first-line: Topical pimecrolimus or tacrolimus as alternatives to highly potent steroids due to better short-term safety profile 1
• Second-line: Narrowband UVB (NB-UVB) phototherapy only if conservative treatments fail, for widespread vitiligo, or localized vitiligo with significant QOL impact 1
  • Reserve for darker skin types (III-VI) 1
  • Safety limit: Maximum 200 treatments for skin types I-III 1
  • Monitor with serial photographs every 2-3 months 1

For Adults:

• Topical steroids: Potent topical steroids can induce repigmentation but with risk of skin atrophy 1
• Topical calcineurin inhibitors: Pimecrolimus or tacrolimus as alternatives with better side-effect profile than highly potent steroids 1
• Phototherapy: NB-UVB preferred over PUVA due to greater efficacy and safety 1
• Combination therapy: Topical tacrolimus with Excimer UV radiation may enhance repigmentation for UV-sensitive sites 1

Depigmentation for Extensive Disease:

Only consider if:

• Patient has >50% depigmentation from vitiligo 1
• Extensive depigmentation on cosmetically sensitive areas (face, hands) 1
• Patient is adult (not recommended for children) 1
• Patient accepts permanence of never tanning 1

Depigmentation agents:

• Monobenzyl ether of hydroquinone (MBEH): 69% achieve total depigmentation within 4-12 months, but 4/11 had recurrence 1
• 4-methoxyphenol (4MP): Similar efficacy to MBEH 1
• Q-switched ruby laser (QSRL): Faster onset (7-14 days), fewer side-effects, but limited evidence 1

Psychological Support:

• Assess psychological impact and QOL effects in all patients 1
• Offer psychological interventions to improve coping mechanisms 1
• Counsel parents of children with vitiligo 1

Associated Conditions Screening:

• Screen for autoimmune thyroid disease: 34% of adults with vitiligo have thyroid disease 1
• Consider screening for: Other autoimmune diseases, ocular/auditory abnormalities, metabolic syndrome 6

Critical Pitfalls to Avoid

• Do not perform partial biopsies on suspected melanoma/CMN - always full excision with margin to avoid understaging 4, 5
• Do not use laser or electrocoagulation for biopsy - destroys tissue needed for histopathology 4
• Do not exceed 2 months of potent topical steroid use in children due to atrophy risk 1
• Do not recommend depigmentation for children with vitiligo or adults with <50% involvement 1
• Do not ignore family history - 10% of vitiligo patients have positive family history 3
• Do not forget Wood's light examination for monitoring vitiligo treatment response 1