INSTRUCTION

Look at this patient's skin.

SALIENT FEATURES

History

• Itching.

• Drug ingestion (thiazides, phenothiazines, gold, organic mercurials, chloroquine,mepacrine, methyldopa, quinine, chlorpropamide, tolbutamide, proton pump inhibitors).

• Occupational history (whether the patient is in contact with colour filmdeveloper).

• Hepatitis C (erosive lichen planus is more common).ExaminationPapular, purplish, flat-topped eruption with fine white streaks (Wickham's striae) overthe anterior wrists and forearms, sacral region, ankles, legs and penis.

Proceed as follows:

• Look into the mouth (buccal mucosa, tongue, gum or lips) for a lace-like patternof white lines and papules. (Remember that oral lichen planus must be differ-entiatedfrom leukoplakia.)

• Examine the scalp for cicatricial alopecia.

• Examine the nails for longitudinal ridging, pterygium formation/'rom the cuticle,20-nail dystrophy with roughened nail surface and brittle free nail edge, total nail loss.

• Comment on eruptions that are present along linear scratch marks (Koebner'sphenomenon).

• Comment on the residual hyperpigmented macules that lichen planus leaves inits wake.

Note. The three cardinal features of lichen planus are the typical skin lesions.histopathological features of T-cell infiltration of the dermis in a band pattern, and IgGand C3 immunofluorescence at the basement membrane of the dermis.

DIAGNOSIS

This patient has violaceous, flat-topped eruptions (lesion) due to lichen planus(aetiology) with several scratch marks indicating moderately severe pruritus (functionalstatus).

ADVANCED-LEVEL QUESTIONS

Mention a few conditions that present as white lesions in the mouth.

• Leukoplakia.

• Candidiasis.

• Aphthous stomatitis.

• Squamous papilloma.

• Verruca vulgaris.

• Secondary syphilis.Mention a few conditions in which ulcers can be found in the mouth.

• Erosive lichen planus.

• Pemphigus vulgaris.

• Recurrent aphthous ulcers.

• Beh~iet's disease.

• Stevens-Johnson syndrome.

• Recurrent herpes simplex.

What is the prognosis in lichen planus?

Lichen planus is a benign condition which lasts for months to years. It may be recurrent.Oral lesions may be persistent.

How would you manage these lesions?

• Local measures: local steroid creams or intralesional steroids.

• General measures: PUVA, isotretinoin, dapsone.

• Ultraviolet light to control pruritus

• Mucous membrane lesions: corticosteroids or 'swish and spit' ciclosporin.L.R Wickham (1860-1913), a French dermatologist.H. Koebner (1838-1904), a German dermatologist.