Pigment Disorders

Hypopigmentation:

Generalised: associated with albinism, phenylketonuria, hypopituitarism
Patchy: vitiligo, tuberous sclerosis, morphoea, pityriasis alba, post-inflammatory (secondary to eczema/psoriasis)
Infection-related: pityriasis versicolor
Chemical exposure: hydroquinone
Halo naevus: depigmentation around the mole

Hyperpigmentation:

Genetic: cafe au lait, freckles, Peutz-Jeghers syndrome, neurofibromatosis
Drug-induced: amiodarone (blue grey in exposed areas), chloroquine (blue-grey on face/arms), chlorpromazine (grey in sun-exposed areas)
Endocrine: Addison’s, chloasma, Cushing’s syndrome
Nutritional: carotenaemia, malabsorption
Post-inflammatory: varicose eczema, lichen planus, systemic sclerosis
Other conditions: haemochromatosis, malignant melanoma, chronic venous insufficiency, liver disease, acanthosis nigricans

Freckles and Lentigines:

Freckles: light brown macules, darken with sun exposure, common in redheads, develop in childhood, no treatment needed
Lentigines (liver spots): scattered macules, no darkening with sun, common in elderly in sun-exposed areas

Chloasma:

Asymmetrical facial pigmentation: forehead and cheeks
Common in females aged 20-40
Risk factors: UV exposure, pregnancy, combined hormonal contraceptives, depot contraceptives, cosmetics, perfumes, deodorant soaps
Management: reassurance, avoid triggers, camouflage/cosmetics, consider laser/peeling

Albinism:

Rare autosomal recessive condition
Melanocytes unable to produce skin/hair/eye pigment
Features: white hair, pale skin, pink eyes, poor vision, photophobia, nystagmus
Management: strict sun avoidance, sunglasses, sun protection, monitor for skin lesions (increased risk of squamous cell carcinoma)

Morphea:

Localised scleroderma, distinct from systemic sclerosis
No internal disease association
Aetiology: autoimmune, may follow trauma
Presentation: round oval plaques with indurated erythema, becoming smooth/shiny/white with violet borders
Progress to atrophic hairless pigmented patches
Location: trunk and proximal limbs
Course: usually spontaneous resolution in 3-5 years
Treatment: potent topical steroids may be tried

DERMATOLOGY