Plaque-type morphea (localised scleroderma).
- Cause unknown but occasionally follows injury, pregnancy, viral infections or autoimmune disease.
- Results from excessive deposition of collagen that leads to thickening of the dermis, and/or subcutaneous tissues.
- Commonly presents before the age of 18 but may appear at any age. More common in women.
- Single or multiple circumscribed, indurated, round or oval plaques, asymmetrical and of variable size (1-20cm).
- May occur anywhere but more commonly the abdomen, breasts or thighs.
- Initially mauve colour but later shiny white central area with loss of hair follicles and sweat glands. May become brown.
- May persist for several years (usually up to three to five years but may be much longer) before softening and resolving spontaneously. A brown stain may remain.
- A diagnosis can normally be made on clinical grounds; if necessary confirmed by biopsy.
- No specific treatment is known to treat this condition. Potent topical or intralesional steroids may help to reduce inflammation and prevent progression.
- Late-onset epidermal naevus.
- Usually occurs in males in prepubertal period to late teens.
- Cause unknown but thought possibly to be related to a gene defect and triggered by androgens.
- Patient presents with the appearance of a unilateral, flat, brown patch, usually in the shoulder region or upper chest.
- May gradually extend for some years, thicken and develop hairs in the area.
- Acne may develop in the naevus.
- Diagnosis may be confirmed by biopsy.
- Treatment is unnecessary unless for cosmetic reasons.
- Patients should be advised to avoid sun exposure as it will increase the discolouration.
- Laser or electrolysis may be used to remove hairs. Laser treatment can improve pigmentation but can occasionally worsen the condition.