Lichen planus pigmentosus (inversus) L43.8

Pock, 2001

Rare brownish coloured variant of the classic Lichen planus, often located in the large articular flexures, in which the characteristic red-violet colour of the Lichen planus is supplemented or completely replaced by a brown colour component.

Has been described preferentially in Caucasians and Asians.

Worldwide, about 50 cases have been described so far (note: such numbers, however, say little about the actual prevalence of lichen planus pigmentosus inversus).

Affected are adults between 40 and 60 years of age. In children this clinical picture has not been described. w>m=2:1

Lichen planus pigmentosus occurs mainly in the intertriginous areas, such as axillary, popliteal, submammary, inguinal, vulvar and penile areas.

Well-demarcated, disseminated, 0.2-0.5 cm, only slightly pruritic, purplish-brown or homogeneous brown patches are found. These may confluence to form extensive, irregularly configured, patches (see Fig.). The lesions tend to be chronic, lasting months or years.

The histology of this lichen planus variant shows the characteristic phenomena of lichen planus, with lichenoidal infiltrates in band form, mostly only minor orthohyperkeratosis (intertrigines) and a conspicuous pigment incontinence.

• Fixed toxic drug exanthema
• acanthosis nigricans
• Candidaintertrigo
• Erythrasma
• Ashy dermatosis

1. Chen S et al (2015) Lichen planus pigmentosus-inversus: report of three Chinese cases and review of the published work. J Dermatol 42: 77-80
2. Ghorbel HH et al (2014) Lichen planus pigmentosus inversus. Indian J Dermatol Venereol Leprol 80:580
3. Murzaku EC et al (2014) Axillary lichen planus pigmentosus-inversus: dermoscopic clues of a rare entity. Diagnosis: lichen planus pigmentosus (LPP). J Am Acad Dermatol 71:e119-20
4. Pock L et al (2001) Lichen planus pigmentosus inversus. J Eur Acad Dermatol Venereol 15: 452-454
5. Schmid C et al (2018) Slate grey patches in both armpits. Dermatologist 69: 177-179
6. Sindhura KB (2015) Lichen planus pigmentosus: a retrospective clinico-epidemiological study with emphasis on the rare follicular variant. J Eur Acad Dermatol Venereol doi: 10.1111/jdv.1345