Melanodermatitis toxica L81.4

Exogenously triggered, chronic phototoxic, partly also photoallergic reaction with post-inflammatory pigment incontinence.

Probably identical with the clinical picture described by Riehl(Riehl melanosis). S.a.u. Melanosis perioralis et peribuccalis.

• Caused by contact with lubricating oil and its derivatives, tar fumes, uncleaned petroleum jelly, phototoxic and sensitizing substances.
• Melanodermatitis toxica as well as melanosis and Riehl's melanosis are the expression of a mostly subclinical chronic persistent photosensitive reaction. Discrete superficial dermatitis leads to melanocytic hypertrophy and hyperplasia. As a consequence of these processes, increased epidermal pigmentation and vivid pigment incontinence occur. The dermal pigmentation essentially determines the dark colour (brown to slate grey) of the lesion.

Strict avoidance of the causative substances (mostly fragrances, perfumes, cosmetics, medicines). Slow regression is possible if the cause is avoided.

As a rule, over-painting of disturbing hyper pigmentations (e.g. Dermacolor) and light protection agents (e.g. Contralum ultra, Anthelios) are the most sensible solutions. Depigmenting external agents like hydroquinone cream(e.g. Pigmanorm) and the more effective combination of hydroquinone-hydrocortisone-Vit. A-acid (e.g. Pigmanorm) are not very useful as it is not only an epidermal pigment but also a dermal pigment which has "dripped off" there in the course of the chronic inflammatory reaction.

1. Hoffmann E, Habermann R (1918) Medicinal and industrial dermatoses caused by war substitutes (Vaseline lubricating oil) and peculiar melanodermatitis. Dtsch Med Wochenschr 4: 261-264
2. Kang HY (2012) Melasma and aspects of pigmentary disorders in Asia. Ann Dermatol Venereol 139 Suppl 3: 92-55
3. Khanna N et al (2011) Facial melanoses: Indian perspective. Indian J Dermatol Venereol Leprol 77:552-563