Lichen planus exanthematicus L43.81

Acute, exanthematous form of lichen planus. In contrast to classic lichen planus, the grouped arrangement of papules is often absent in the eruptive exanthematous variant and gives way to a disorderly disseminated distribution pattern.

Exanthematous lichen planus tends to form extensive plaques that resolve only marginally into individual papules.

The development of erythroderma is possible (although extremely rare).

Unsolved.

Relatively often drug-induced (e.g. gold salts, antimalarials, beta-blockers) or occurring after vaccinations. The term "lichen planus-like drug eruption" or "generalized lichenoid drug eruption" is also used for this form of manifestation. S.u. Drug exanthem lichenoides.

Lichen planus-like exanthema is also observed in chronic graft-versus-host disease (see figure). Furthermore, after percutaneous radiotherapy (Kluger N 2017) and after vaccinations of various types (Rosenblatt AE et al. 2015)

Children as well as adults.

Adults:

• Trunk, extremities with emphasis on flexor sides of wrists and forearms, face remains free.
• Hands and feet often involved
• Mucosal involvement (30-40%): Penis, oral and genital mucosa.
• Capillitium

Children:

• Extremities (70%)
• Trunk
• Mucous membranes remain free
• capillitium remains free
• no palmo-plantar involvement

Initially about 0.1-0.2 cm in size, bordered by the natural furrows of the skin, raised, plateau-like, smooth, lacquer-like shiny (as if polished), distinctly itchy, red papules. With prolonged persistence, the typical livid hue may give way to a brown basal hue.

Aggregation of several papules with formation of plaques of different sizes. In long-term plaques, the typical "polished smooth surface" may give way to a verrucous, then sometimes whitish surface texture. Histologically, this clinical finding is accompanied by vigorous acanthosis and orthohyperkeratosis. No parakeratotic keratinization.

The diagnostically important surface reflection of the (classic) lichen planus papules is best recognized with light incident from the side.

Further characteristic of the exanthematous form are linear arrangements of the efflorescences in scratch or rub marks (see below Köbner phenomenon = isomorphic irritation effect).

Important: The patient responds to itching by rubbing, not by scratching the efflorescences. This distinguishes the disease from atopic dermatitis.

Oral mucosal involvement (see also Lichen planus mucosae) is observed in > 50% of patients. Symmetrical, reticular or nummular white plaques, also disseminated, 0.1-0.2 cm white papules of the buccal mucosa and/or tongue and/or gingiva are typical (Explanation: the whitish discoloration of the papules/plaques corresponds to the "wash skin effect" of the hands. Lichen planus efflorescence shows a keratinization tendency also in the mucosal area; horn absorbs water due to oral moisture, swells and then appears whitish, opaque due to the strong refraction of light. This distinguishes it from the non-keratinizing, healthy oral mucosa).

The erosive lichen planus of the oral mucosa, which is usually painful, is a special case.

Genitalia, especially the glans penis and the vulva, are affected in the form of anular or circular, whitish but also red or erosive (therapy-resistant) plaques (see below Lichen planus mucosae/ Lichen planus vulvae).

Capillitium (see below Lichen planus follicularis capillitii).

Nails: S. Lichen planus classic type(trachyonychia).

According to the Lichen planus.

Analysis of the triggering cause in question.

• Discontinuation of possible medication. Local glucocorticoid therapy in case of severe itching.

If necessary, reduce internal therapy with prednisone equivalent, initially 10-20 mg/day p.o., maintenance dose adapted to the disease.

Azathioprine, sulfasalazine, methotrexate, acitretin were successfully used. These therapy modalities should always be evaluated under the aspect of the self-limited course of the disease.

Experimental: Apremilast, an oral PDE4 inhibitor, which was successfully tested in a smaller monocentric study for the lichen planus exanthematicus.

Rather cheaper than the classic Lichen planus. Frequently self-limated course within a 3-6 month period!

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2. de Golian EW et al (2014) Lichenoid drug reaction following influenza vaccination in an HIV-positive patient: a case report and literature review. J Drugs Dermatol 13:873-875.
3. Fessa C et al (2012) Lichen planus-like drug eruptions due to β-blockers: a case report and literature review. Am J Clin Dermatol 13:417-421.
4. Noruka EN (2007) Lichen planus in African children: a study of 13 patients. Pediatr Dermatol 24:495-498
5. Kluger N (2017) Radiation-associated lichen planus: a case report and literature review.
6. Acta Dermatovenerol Alp Pannonica Adriat 26:105-108.
7. Omidian M et al. (2010) Efficacy of sulfasalazine in the treatment of generalized lichen planus: randomized double-blinded clinical trial on 52 patients. J Eur Acad Dermatol Venereol 24:1051-1054.
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9. Rose AE et al (2011) Erythrodermic lichen planus. Dermatol Online J 17:26
10. Rosenblatt AE et al (2015) Cutaneous reactions to vaccinations. Clin Dermatol 33:327-332.
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12. Vazirnia A et al (2014) Acitretin for the management of generalized cutaneous lichen planus. Dermatol Online J PubMed PMID: 25244164.